How can you gain selective protection from Sending?

Question

Inspired by this answer by keithcurtis regarding what it takes to be "familiar" enough to target someone with the Sending spell:

A peasant might not know their king personally, but may have heard him speak and seen him on parade often enough for a DM to say this is familiar.

Assuming that my GM follows this interpretation, then I really feel bad for my king. Everyone in his realm capable of casting Sending will constantly do so to tell him how much they hate paying taxes, how unfair his laws are, how his foolish foreign policy will get them all killed, why he doesn't do anything about those homicidal PCs, etc., etc. He won't be able to concentrate on governing, enjoy his limited free time or even sleep due to constantly being distracted by Sendings from disgruntled citizens.

He really would like to behead some of these annoying people to make an example out of them, but unfortunately he can't because the Sending spell says:

The creature hears the message in its mind, recognizes you as the sender if it knows you, and can answer in a like manner immediately.

The king won't know most of his subjects personally, so he can't retaliate in any way but abusing them back.

What he needs is a spam filter.

I would like to help my king by casting some spell which protects him from sending. But I am sure he doesn't want to block it out completely, because some of his vassals might have good reason to cast Sending to inform him about some very urgent matter which requires his attention.

What are my options to block Sending from everyone but a selected group of people?

Answer 1

Ring of Mind Shielding (and a DM who cooperates)

Note: This depends on your DM accepting an interpretation of how a magic item works that is not explicitly clear.

If you are still being irritated by people spamming you with Sending, you may be able to justify the use of the Uncommon magic item: Ring of Mind Shielding.

The description for the Ring specifies...

Creatures can telepathically communicate with you only if you allow it.

DMG191

And Sending's description says...

The creature hears the message in its mind

PHB274

While it does not explicitly state that Sending is a telepathic communication, the plain language interpretation implies that it is. Thus, you could easily justify that a Ring of Mind Shielding is a ward against Sending. And 'If you allow it' could be interpreted that the King can maintain a 'Mental Whitelist' of people who are allowed to communicate with him telepathically.

However...

Very few people can cast Sending

Unless you are in a very high magic world, Adventurers are rare. You can generally tell that they are rare because there tends to not be competition for all the quests you are doling out. And when big crises hit...the PC's party is almost always the only band of adventurers really doing something about that crisis. (Exceptions exist, of course). While no official statements have been released regarding demographics, we can look at a few settings for some ideas.

Faerun has not had any official material released on it, but makes it clear that Adventurers are Exceptional. Most of the numbers I have seen give a (generous, IMO) rating that maybe 1 in 100 people can become an adventurer. A full 1% of the population. If you then assume that about half of them reach the next level each time...the rest die or quit. Based on that: 0.0625% of the population will ever reach 5th level. So, in ten-thousand people--six have ever reached 5th level.

Eberron takes this even further. Characters with Adventurer levels are exceedingly rare. Small fractions of a percent of the population have even a single Adventuring level. And characters with 3-5 levels are famed war heroes. Admittedly, Eberron doubles down on the rarity of high-level characters.

Additionally, only three sorts of PC Class can cast Sending: Bards, Clerics, and Wizards. Even if you assume an even distribution (which you shouldn't) that means that 1/4 of Adventurers (3 of 12 classes) can use Sending.

So, out of your 6 in a ten-thousand characters, 1.5 of them can use Sending. On top of that, Bards can only use Sending if they specifically select that spell when leveling up.

So, we'll round down to 1 in ten-thousand as a (generous) nod to the fact that Clerics and Wizards are likely more rare than Fighters, Barbarians, and Rogues.

Note that this 1 in a thousand includes the Adventurers who are higher than 5th level as well, and whose concerns are thus even more removed from petty concerns like 'taxes.'

To again draw on The Realms for example...while the numbers given vary, the most common count is that there are about 130,000 people living in the city of Waterdeep. With an average distribution, that means there are about 13 people in the entire city who can cast Sending. If your King doesn't know the identity of those 13 individuals, he's not being very smart.

Now, granted, Waterdeep does NOT have an average distribution...the place attracts Adventurers like honey. But those Adventurers are there to adventure, so...

The people who can cast Sending probably have better things to do than annoy the King

Most likely, these are Clerics and Wizards. Assuming they are not out adventuring...Clerics are likely working at a temple--healing the sick, proselytizing, and otherwise serving their god. Wizards likely have their noses buried in their spellbooks, are training apprentices, or are working for some nobleman as their court mage.

A 5th level or higher Spellcaster is a powerful resource. They aren't likely to just be sitting on their hands, bored enough to irritate the King (and they may very well get preferential treatment from the nobility anyway--Makes sense to keep the person who can heal mortal wounds on your good side).

Summary

If you have a cooperative DM (or are the DM) a Ring of Mind Shielding can do the trick. But you probably don't need it.

Answer 2

Homebrew Spells.

Unless your PC is a king, they are not restricted to the spells listed in the PHB, XGtE, EE, or any other published book. There is nothing restricting NPCs (including your king and/or their court wizard) from using spells that PCs simply do not have available to them.

In my games, there are two broad types of casters: battle casters and everyone else. Consider these classes to be the magical equivalent to Army Sappers and the Army Corp of Engineers.

Army Sappers are trained in 'combat engineering'. While being shot at, they can determine the amount of explosives required to blow open a door. They can lay down an effective minefield quickly and safely. They can design a bridge that will be possible to lay down under fire, and won't fall down or be easy for the enemy to destroy. The would not, however, be especially skilled at building a dam, or trying to design flood protection.

Army Corp Engineers are trained in civil/structural engineering. They spend years designing dams, building up flood protection structures, designing military bases, etc... But they would not do well trying to determine exactly how much C4 is needed right here, right now, especially while people are being shot all around them.

Both are skilled, and both use engineering, but neither could do the other's job's very well.

So, in my world, magical PC's are all Army Sappers. They practice casting under pressure, in casting spells that take fractions of a second to cast, and in spells designed to damage the enemy, or support their allies. There are other casters (ACE's) who specialize in being able to cast stronger spells, but which take longer to cast. These spells are next to useless in a fight (not damaging, take too long to cast, vulnerable to interruption, etc..), but can do things that PC's can't. Like restrict teleportation into the treasury, ward the throne room from telepathy and charm spells, protect the kings bedroom from scrying attempts, etc... This is well within the DM's authority, and my players seem to enjoy seeing other casters that aren't just NPC's with PC classes.

Answer 3

The question has the answer in it. Commoner is a class and a non-magical one at that, so unless a whole bunch of commoners suddenly went to Wizard school, which in and of itself would take a long time to progress, he really shouldn't have to be protected from Sending.

That said, there are a few magical ways to prevent Sending, such as Antimagic Field (Targeted Effects. Spells and other magical effects, such as magic missile and charm person, that target a creature or an object in the sphere have no effect on that target.) but that stops all Sendings and not just some.

On a final note, perhaps the King could have some pretender who goes out and does everything for him so that it's actually the duplicate who gets the Sendings rather than himself.