Or at the very least I hope we all understand that recording audio of guests in your home without letting them know about it is a dick move and also a little creepy. If I was hanging out at my friend's house and later found out he'd been recording our conversation without telling me, I'd find that pretty weird, and it would definitely affect the friendship.
If it was just that he had a security system set up and it happened to record audio, that probably wouldn't bother me. But if he was using to spy on me while out of the room (say to check what people were saying when he's not present), that goes back into creepy territory for me.
