My four stages of a 'flash sale' purchase.
Days 1 - 3: fully expect it to be not honoured.
Days 3 - 7: anxiously optimistic.
Days 8 - 30: cautiously confident.
Day 30+ : start looking at positioning flights. accom.
This is only where I book direct with the airline though. Some OTA's only do a once a month settlement with the airlines so I leave even longer if booked via one of them.
So at the moment, i'm cautiously confident
I never ever call the airline until the first people have reported back they have flown with no issues. The way I see it, if I know i'm flying flat for less than £500 return I can forgo the best seats if it involves phoning the airline. ANY would work for me.