I was on a recent Southwest flight and paid extra for an extra-legroom seat. I also checked my 21-inch roller bag, specifically so I could keep the additional space around my seat clear and make the most of the legroom I had paid for.
After boarding, I placed my backpack in the overhead bin. A passenger later walked by and complained about backpacks being stored there. I'm not sure whether that passenger was seated in an extra-legroom row or not.
Shortly afterward, a flight attendant began removing backpacks from the overhead compartments and handing them back to passengers, apparently to free up space for larger carry-on bags.
This left me wondering about the policy and etiquette. If someone has already checked their larger bag and paid for a premium seat, is it reasonable to use the overhead bin for a backpack to preserve the legroom they purchased? Or should overhead space be reserved primarily for larger carry-on items regardless of seating location?