No you are not BU. I see no reason short of losing one’s phone why it is not the norm to let someone know if you are unavoidably going to be late, whether it is friend or family, or to ring and cancel if you no longer need an appointment. Otherwise you are saying, My time is my own and I don’t care about yours. Especially bad in the NHS. Quite a few No Shows at CAB too.
Ah yes, I know what you mean. It's the "waiting in for the plumber" scenario, only for you it's family.
If I have a situation like this, as I have, frequently, I leave a note on the door, in an envelope with the visitor's name on it. "I'm so sorry, I thought you were coming at ........ and I've been unavoidable called away. Please ring me (or I may say "I'll ring you") ' Then next time I have contact with that person, I advise them to PLEASE let me know if, in future, they've been held up later than the arranged time. All this can be done with kindness and humour.
But isn't it annoying until you've got things clarified?
To set the scene...I work full time but have weekends off. We are leaving on vacation on Wednesday which just happens to be my grandson’s 5th birthday. My son works odd shifts, and my DIL’s mother is visiting from out of town, so it is a bit difficult to arrangeA get together. I thought it would be nice to meet for coffee downtown yesterday, and I could give my GS his gift. DIL agreed to meet for coffee at 2, then just before changed it to 3. Then she said she wasn’t well so would come by for coffee visit in the morning. I have made a treat, got ready for a visit, but it is almost noon, and no word. I have some running around to do, and am taking out my MIL who is 89 for dinner this evening, so don’t really want to wait around all day then have them all show up at 4 this afternoon, then have to rush them out the door. I love them all and am more than happy to have a visit, but wish she would commit to a time.