I will start by saying I am a fairly relaxed person when it comes to the house. I like tidy, but am not obsessed about cleaning etc.
A few years ago, after my divorce, I bougt my current house & had a downstairs toilet installed. Because of space constraints, it is off the kitchen. I have a rule that basically it's only for No.1's. I sort of assumed that most people would realise that anyway, firstly because it is near the kitchen, and secondly because it isn't exactly soundproof 
Anyway, a friend & her DH visited yesterday. I will add that he has history - he has on at least one previous occasion taken himslef upstairs & sat in that loo for a 'session' ( apologies if you're eating
) but yesterday he excelled himself. We were sitting in the lounge chatting & he disappeared out of the room. I went in to the kitchen a few minutes later & he shouted through the door to announce where he was. His DW rather nervously reminded him about my rule ( knowing what he is like, I suspect) to which he replied 'oh dear'.
Whilst I can see the funny side of it, I do think it is rude....or AIBU?!
I'm thinking of putting a bloody great big sign on the door now!!!!