I have never booed a player, but then I dont think Ive ever been in a tournament where someone has done something which constituted booing (bar Samantha Stevenson stealing my chair, but shes not a player).
THE GIRLS ON TOUR!
I have - and I love tennis. Doesn't mean I love it when players are complete twats.
I didn't boo, but was making loud disapproving noises along with many others at conchita at eastbourne last year when she was abusing one of the ball kids, completely embarassing the kid for no reason at all. Can't remember which round it was.
No different to if someone's harassing someone on the street.
I never really did it, because it is very rude for the players... But I was very close to boo Maureen Drake at the Challenge Bell in Quebec City last year against Milagros Sequera. Her attitude was just making me angry ... Even if she's Canadian, I was feeling like doing it but I just didn't...by respect.