A fair few times people have mistaken me for an attendee or general nobody at an event I am running or where I am a speaker, not sure on those occasions if it was my baby face or the wheelchair.
I was once totally ignored and dismissed by someone at a Trade show, unfortunately for them I had been invited by their boss to discuss something mutually beneficial but probably better for them than me... When I did finally get someone to speak to me, they told me I couldn't be me (yeah, no, I don't get it either) because ... and then he waved at my wheelchair... and then turned and walked away.
Boss was v apologetic after the event but by that point I'd gone elsewhere.
Weirdly though, theres been at least two occasions I know of (and so possibly more I don't know about) where people are absolutely convinced they've met and talked to me and they definitely haven't.
One person I actually asked 'Oh I thought you were going to come and say hi at x Conference, but I seem to have missed you', told me he'd had several conversations with me, what was I on about.. and we did work out who he had talked to (who knew there'd be two people in purple wheelchairs!)
Another person told me it was super to have met me ... and we hadn't, and I have never worked out who it was she met, though potentially could be the same person as the previous one.
I don't know her so ... no idea if shes pretending to be me on purpose (unlikely but who knows) or what!