Imo wrongful accusation is one of the worst things that can happen in terms of how it makes you feel. Especially a bummer with how much you like the event and how you go out of your way to be supportive
It sounds like you handled the interaction really well. Even though it sucks that it happened, I think part of the reason it made you feel bad is doing something like that would be so out of character, which speaks volumes to your own personal character. While you feel bad about the interaction, you should at least feel good about that.