This is the major issue I have with the Alaska boarding process. I'm Delta GM but, as PDX is my home airport, it's easier to fly Alaska for certain routes. Last week I missed the "partner elite" boarding call and boarded with everyone else who "agreed to not use the overhead bins." The gate agent saw my roller bag, snidely said "is that going under your seat," I said "I'm sorry - I thought you were boarding elites," she let me board after looking at my eBoarding pass, but I boarded into coach and tossed my roller board into the overhead bin. None of the FA's said "boo" to me. Maybe its because I was in the exit row, but there really does not appear to be enforced once people get on board. I can totally see this being something which kettles take advantage of.