Is it possible or am I just forgetful?

[KittybotANI]

I'm aware of the fact that old villagers who've moved out can appear on Main Street. Is it possible for villagers who've never lived in your town to show up there? Bluebear is hanging out in my shopping district and I'm almost positive she's never lived in my town.

 

[Reindeer]

Only villagers that have lived in your town will show up there.

 

[Jesusfreakette]

I actually have heard of that rarely happening to other people, actually. It's a glitch likely, maybe caused by villagers entering your "Void" via Wi-fi, or the game just getting confused.