Sorry for bumping an old thread, I do have a similar issue here. Booked BOS-YUL on united.com, economy, non-stop, AC operated, UA flight number (UA 8XXX). But both UA and AC sites say I need to pay for bags, even though I am 1K. I actually don't plan to check bags, but do want *G benefits if necessary. Looks like AC took my MileagePlus number, but may not recognize my *G? Will this issue be resolved at check in, or should I take an action before hand?