Personally I’d always knock, I’d rather not open the door when someone’s having a Tommy Tank whilst on t’internet. 
Dipper_Dave:
I had me door opened once and got caught with me pants down, full snorkel gear and luncheon meat job. It was me bathroom door, bloody kids told if the taps runnin I’m doin stuff.
aye, nothing worse when the half the family walk in when ya trying to snap one off.
midlifetrucker:
Surely this is a wind up. Do people really get wound up over such trivia…
I can’t speak for anyone else but it doesn’t wind me up, I just think it’s a bit rude that’s all.
is that you secretelephant on i’m a celebrity ,the guy in the shop on the dingo dollar challenge ,it cracks me up when they get the question wrong the way he shuts the door with such venom