On the other hand, Monday a week ago they were telling people who arrived at 3 pm for an 11:45 pm flight that they wouldn't open check-in again until 8 pm. (There was special rebooking and voucher handling of passengers from a Sunday evneing flight that had been cancelled that Monday morning after being delayed; this is the only reason why there were even tons of Cathay check-in people around at that hour, I think.) So 4 hours might be stretching it at certain times. (OTOH, 5 hours for the 1:45 am flight is probably no problem, since check-in for it overlaps with check-in for the 11:45 pm flight.)