Yesterday I was stood up.
An acquaintance and I made plans for her to come over for brunch. She had to leave by one, so I thought I'd make a turkey frittata and salad.
She never came. She never called.
It's not nice to do that to people.
If you can't make an appointment, call the person. Even if it's at the last minute because you forgot. At least let them know that there's no reason for them to finish cleaning the living room or whatever.