...that is self apparent to most of us. The request is wasted on some others, whether providers or hobbyists.

Unfortunately providers are as equally to blame as the guys are in this regard.

There is rarely a valid reason why a simple call or email can't be made so the other person isn't stood up. But common courtesy isn't all that common in the hobby some times!

... the same people that can't be bothered to call a hobbyist or provider are the same people who can't be bothered to cancel a restaurant reservation after double-booking or finding a better place.  Unless there's some accountability this will always be inconsiderate shitheads who will do this.

Trust me, if a provider does not email/call you to postpone and/or cancel her appointment, she is NOT a good provider. All good providers go out of their way to call you and email you to let you know. I had even had a provider who on her way to my hotel had a flat tire and she paid me for the hotel suit that i booked and only asked for 50% of her gift next time i saw her. This is a sign of good businesswoman. Of course, i would repeat with her over and over and over because she is a good person who cares about her clients.