Those aren't too bad of flakes.
I have had an "OMG, I completely forgot about this shop and now it's closed" flake. Had to reschedule for the following day.
I've forgotten to add a shop to my calendar amidst 10 others of the same, and almost flaked. Would have, had the scheduler not emailed me, noticing I hadn't viewed the guidelines for it.
I've done a dining shop where I requested a broad open window, not knowing exactly when I could fit it on. Ended up being the last day of the window, that I could do it. Got there and the health department had shut down their kitchen a couple days before. Only their bar was open. I did my required drink at the bar, but left after, since they couldn't serve food. Kinda glad I flaked on that one, actually, now that I think about it. Still got paid and reimbursed, except it was just for the bar tab and tip.
------------------------------------------------
Plan the work. Work the plan.