Who makes the charisma save when Scattering out of a Forcecage?

Question

The spell Forcecage is pretty handy for blocking magical teleportation getting the caster out of the cage (except when it's not):

If the creature tries to use teleportation or interplanar travel to leave the cage, it must first make a Charisma saving throw.

But both Scatter and Vortex Warp target creatures other than the caster:

An unwilling creature must succeed on a Wisdom saving throw to resist this spell. You teleport each affected target to an unoccupied space that you can see within 120 feet of you.

And

The target must succeed on a Constitution saving throw (the target can choose to fail), or the target is teleported to an unoccupied space of your choice that you can see within range.

But Forcecage seems to be written as though the one doing the teleporting is the caster.

I can see three options for a caster trying to get somebody out of the cage:

• The caster makes the charisma save, as it's the one doing the trying, regardless of whether they're in the cage or not, despite not trying to leave themselves.
• The teleportee makes the charisma save, as their the one being teleported, even if they didn't cast the spell.
• Nobody makes the save, as the wording of Forcecage doesn't prevent this from happening

Is there anyway to figure out which of this is the correct option/most well supported?

Answer 1

RAW, Forcecage's save only applies to spells cast by the target.

You quote the relevant text in your question (emphasis mine):

If the creature tries to use teleportation or interplanar travel

Contextually this is unambiguous: only the targeted creature is forced to make the saving throw when it casts teleportation or interplanar travel spells.

RAI, unclear.

The above argument hinges on the phrase "tries to use". It's not perfectly certain that this spell was designed to be foiled so easily. Your DM may interpret shouting "Hey, cast scatter on me!" as trying to use teleportation.