Being ncns'd isn't a question of if, but of when. The longer you hobby the more likely it becomes that the inevitable will happy to you...regardless of how awesome you are Bair
Barring the person can prove they were unconsious in the hospital, or something like that, my suggestion is you scratch the person from your list, even if they're a regular. A true NCNS shows a clear lack of respect and warrants nothing less. If they offer to make it up to you, and you accept, then you're saying it's OK to be disrespectful to me in the future. I say BS, no thank you, and I don't care who you are I'm posting that you NCNS'd and are a disrespectful person. That goes for providers or hobbyists. NEVER NCNS.
I'd rather hear - I'm sorry I'm going to have to reschedule because I'm getting my brains banged out by your worst enemy - than be NCNS'd.
Makeups (extended sessions, big tips, whatever) are appropriate when lesser issues came up like needing to reschedule a trip or appointment, needing to end an appointment early, or accidentally going over time. These are good business practices, regardless of the business. There's nothing appropriate to address disrespect.
IMHO