have you ever walked in on someone

[This user has not been convicted of 34 felonies]

I've been walked in on, yes.

[Gustaf]

I accidentally walked in on my flatmate once. But they didn't notice and I got out quickly. I've heard a lot through thin walls though.

[RogueBeaver]

No, thankfully.

[Grumpier Than Uncle Joe]

Ha ha, no.  In college my roommate and I put a piece of tape hanging down from the wall phone (yes, kids they did exist) that was right next to the door.

Walk in, grab the tape and put it over the keyhole and the other poor bastard had to knock on some doors to get some sleep.