Originally Posted by
gary_nj
I find that I sometimes get strange sequence numbers if my flight is, for example, a continuation of a flight that originated in Europe. So, if I am checking in for the EWR-SFO portion of CO 41 (which operates FCO-EWR-SFO), I sometimes get a higher-than expected sequence number. Just one for the OP to keep in mind if he/she sees an unexpected number.
Not only that, but if you're trying to get on a flight as standby or last minute or something, and people misconnect or no-show, it's also possible to get a sequence number higher than the number of seats.
Once one is offloaded from the flight, their sequence number is not reused.