My favorite perverse incentive lately is the trend of only allowing larger bags in the overhead bans. If you try to put a smaller item like a backpack up there,

My favorite perverse incentive lately is the trend of only allowing larger bags in the overhead bans. If you try to put a smaller item like a backpack up there, they will insist that you put it under the seat in front of you instead. The workaround is obvious: always travel with a larger bag, even if it's mostly empty.