I have to jump in here too.

When I'm singing and playing and a person comes up to me to talk I put my hand up indicating to them to way till I'm thru with this song and they usually wait and I talk to them after the song.
If a person is rude and they push themselves onto me or tries to do something else to distract me while I'm singing and playing, that's where it ends for me.

This has happened a few times to me.

I'm doing my thing and a women comes up and stands right in front of me and starts waving her hands like a crazy person....well, I never tollerate that. The dance floor is full, I press the Stop button and I say over the microphone nice and loud, "Lady what do you want that can't wait untill I'm thru with this song. I cannot sing and play and talk to you at the same time." And then I appologize to the audience for the interruption. I tell the people how rude this women is. The audience gives me a round of applause and the women literally crawls back to her table.

This above scenerio usually happens at a condo dance never at an assisted facility or private party.

I've been in this business too long. That's how I deal with a rude person.