Originally Posted by
mfkne
Hé didn’t present him for boarding but for check-in, admittedly through no fault of his own.
Incorrect.
The operating carrier refused to permit OP to fly despite OP having a ticket & reservation & having presented well in advance of the minimum time.
Terms such as "check-in" are relatively meaningless bits of administrative process. Nor, quite properly, do they exist in the Regulation.