From the hobbiest prospective, I typically over communicate as providers often booI k the hotel and have expenses. If a provider flakes on me at most I am out gas. This makes me look at flakes differently. I look at flakes as a way to get out of the house. I usually sent a text about an hour befere I leave. If she doesn't reply, I consider the appointment cancelled. If she replies I know its on. About a half hour before I send a text "should be on time." When I arrive I sent a text saying "here". If she does not reply to the text I wait 10 minutes, getting out of the car and going for a walk. If she has not responded by end of my walk I consider it a flake.
I use this flake as an opportunity to find a new resturant or bar and grill. I have been known to sent a text with a picture my beer and food with a Thank You for not wasting my money. If the provider/hobbiest is not willing to give you the common courtesy to let you know they cannot make it, chances are they would have been a problem.