Does someone realize they were charmed after the effect of the Glamour bard's Enthralling Performance wears off?

Question

I have been playing a College of Glamour bard in the Tomb of Annihilation module. They get the Enthralling Performance feature at 3rd level when they choose the subclass (Xanathar's Guide to Everything, p. 14):

If you perform for at least 1 minute, you can attempt to inspire wonder in your audience by singing, reciting a poem, or dancing. At the end of the performance, choose a number of humanoids within 60 feet of you who watched and listened to all of it, up to a number equal to your Charisma modifier (minimum of one). Each target must succeed on a Wisdom saving throw against your spell save DC or be charmed by you. [...] This effect ends on a target after 1 hour, if it takes any damage, if you attack it, or if it witnesses you attacking or damaging any of its allies.

If a target succeeds on its saving throw, the target has no hint that you tried to charm it.

According to the description, the target does not become aware of the fact that someone attempted to charm them if they succeed at their saving throw. However, it doesn't say anything about what happens if they fail their save and the charm wears off.

Once the effect of Enthralling Performance wears off, do those that were previously affected by it know they were charmed?

Answer 1

The intent of this ability is kind of joyfully goofy — the bard's personality and performance are so bewitching that the listeners become super fans. From a designer interview:

Also, aesthetically, Mike [Mearls] and I early on talked about essentially having figures like Freddie Mercury in mind, so this Bard, it was just crazily fabulous and beguiling [....]

We felt there was a place for a Bard that instead was all about the beguiling magic of the Feywild, and so the College of Glamour play testers really liked it, and we refined it to really just enhance what they liked about it and that is: this Bard who is able to beguile people using their class features and not just using spells, a Bard who once they’re high enough level, can make it difficult for people to even attack them because essentially, the people have become their fans because again, full disclosure, in addition to being inspired by stories of Fey creatures and their beguiling abilities, we were also again inspired by the idea of the College of Glamour sort of being a pop star and so there’s a little thread in some of the class features of basically people becoming the College of Glamour’s, that Bard’s fans. We’re going to do what you say. We’re not going to hurt you.

Emphasis mine. Some punctuation added to the official transcript, as it is rather breathless.

With other charm abilities, like the spell friends (as NathanS notes), the "victims" become hostile after the effect ends. That doesn't really play well with the trope here. It may be possible that some rare stubborn person shakes off the influence, but in general, you can't have a pop-rock star with a (possibly slightly literally) crazy fanbase if that fandom wears off when the effect does.

Therefore, I think it's intentional that the ability doesn't mention any negative aftereffects.

Answer 2

It doesn't say

Xanathar's Guide to Everything only says what you've already found; that they don't know that you attempted to charm them if they succeed their save. It doesn't say whether the know that you charmed them if they fail their save.

I checked the wording of Words of Terror feature from the College of Whispers bard archetype, which is similar in nature. From XGTE, pg. 16:

If you speak to a humanoid alone for at least 1 minute, you can attempt to seed paranoia in its mind. At the end of the conversation, the target must succeed on a Wisdom saving throw against your spell save DC or be frightened of you or another creature of your choice. The target is frightened in this way for 1 hour, until it is attacked or damaged, or until it witnesses its allies being attacked or damaged.

If the target succeeds on its saving throw, the target has no hint that you tried to frighten it.

Much the same as the wording for Enthralling Performance, and equally as unhelpful for determining what happens if they fail their save regarding whether they know or not.

Arguments for they don't know

If we consider other ways to charm people, specifically the charm person spell and the friends cantrip, both say that they do know. Given that the Enthralling Performance feature does not say this, we could conclude that if it meant for the target to realise, it would have said so, and therefore because the feature doesn't say this, then they do not know.

From charm person (PHB, pg. 221):

When the spell ends, the creature knows it was charmed by you.

From friends (PHB, pg. 244):

When the spell ends, the creature realizes that you used magic to influence its mood and becomes hostile toward you.

However, these two spells are not all at related to the Enthralling Performance class feature and beyond giving a DM a precedence to rule this way, they don't directly inform us on what Enthralling Performance should do.

Furthermore, if the target doesn't know what happened when they succeed a saving throw, it stands to reason that they shouldn't gain knowledge by failing a saving throw. It seems odd that they should gain from failing something, even if there were other effects at play. Of course, this is just a line of reasoning and ultimately doesn't have any backing from the text.

DM Ruling

Since the rules don't explicitly tell us, then unless we have a Word of God answer (and I couldn't find a Sage Advice on this) then it'll have to be up to the DM to decide on an interpretation of this feature that makes sense to them.

Answer 3

I personally think that it makes sense for them to grow bored of you in the case of Glamour bards, and thus not know you charmed it. However they would want to hear you perform again, as at the time it would have been a pleasant experience. That means you can do regular Performance or Persuasion checks on them now, and if they were hostile, they still allow this check with no disadvantage.

Same with the College of Whispers, but in an opposite sense. Basically. they would be scared enough of your words that you could pull an Intimidation check by simply threatening to have "another little talk" with them.