Some Flight Attendants require the bag must fit wheels in, handle out, in the overhead bins. Sideways, where it takes up half the bin is not allowed. With the 100+ load factors we have right now (every seat full, plus jumps) cabin space is restricted.

The only rule that might be violated is failure to comply with a Crew Member's instructions, but I saw it today and the 22" bag got checked. Mine was crammed under the seat in front of me.