Libby quietly melts into the ether and doesn't reappear until any visitors have gone (sometimes long gone). If we're both caught by surprise by an unexpected knock at the door, and she's in the beanbag, she'll run up the hall to somewhere safe, then run out of the front door again as soon as I've shown the visitor into the living room. Libby even runs away from my mum, who's known her since she was a kitten and comes to stay often. I now call her 'Scary Grandma'!
Jasper, on the other hand, sits on the couch on the verandah and looks everyone up and down, who comes to the door. He's anybody's for a quick pat!