I don’t think it is unreasonable to expect someone to turn up to an appointment, particularly if they are the one who asked for it. Let’s compare.
Today I went to a new place to walk my dogs because someone had posted on our dog Facebook page looking for friends for their Dogue de Bordeaux. I volunteered to drive over and meet them this morning. They chose a park near to them and gave vague indications where they would be.

I walked around for quite a while, fortunately having a lovely time and meeting some very pleasant dog walkers, before I finally made contact with the person who said (via a Facebook post because that was all they could manage) “Oh yeah…meant to message you…”
I wasn’t too mad because I’d had a nice time with my dogs, but it really should have been a minimum requirement to message me to call off the arrangement when the lady’s circumstances changed.
Contrast to my dental appointment. I rang this morning and told the receptionist I had foreboding throbbing coming from below one of my molars. Brilliantly, they fitted me in this afternoon so I was sure to be there, and on time. It’s just what you do.
Oh and in typically “my teeth” ways, the issue is unclear, but probably a sign of a dying tooth which will be a real problem, but the x-ray was obscured by the metalwork from the last dentist who broke my jaw. So yeah.
Back on Monday for another check on it. I’m on the painkillers though because it’s “not right” in there.