Originally Posted by
plucasana
is there a number of weeks that -if gone by after the purchase of an error fare -
could be considered as „now I am safe“?
(just an estimate???)
Absolutely not.
It can happen weeks or months afterwards, or even at check-in if they find one has slipped through the cracks. Or, as Swiss did notoriously a few years ago, downgrade you to Economy from First Class at the gate.