RyanDean

This is what one OF creator said to me when I mentioned something when, after missing his non-sexual musical concert, I asked if he had any upcoming shows.

Hey there! OnlyFans' Terms of Service strongly forbid any discussion of real world interaction, even if that's two creators collaborating together or a musician performing a show. They're very strict about that here!
So I try to find the gent on X/Twitter, RentMen, or some other social media platform so as to not inadvertently jeopardize their OF account. And, yes, OF is arbitrary in its enforcement on such things, but it does tend to be pretty swift/severe when it does opt to do so...

Thanks, all. The consensus does seems to be that the combo of "no communication and no show" is the dealbreaker and that 15-30 minutes is a fair "grace period" in such situations. 
I did find that communicating the boundary of my patience ("if I don't hear back by ___") proved a sanity-saver for me yesterday, so I'll likely carry that forward.
And for those who might be interested:
The gent did ultimately contact me, about two hours after we were set to meet. His story -- if true -- would suggest that he simply had a very bad day, complicated by some truly bad luck. So I'm willing to accept that he may actually be legit, given the enthusiasm of other posters. As for me, I go back and forth on whether I believe the gent's story as I also take come comfort from the not-insubstantial pile of dollars that remain in my pocket.