The difficulty with that has mostly been logistics. It's hard to confirm what people are bringing on as a carry-on until you're literally boarding the plane. T

The difficulty with that has mostly been logistics. It's hard to confirm what people are bringing on as a carry-on until you're literally boarding the plane. Try getting $50 out of someone as they're boarding a plane. A major part of these choices involve whether they're feasible in situations with time pressure and frustrated passengers. Luckily airline staff have huge latitude to help defuse situations with angry customers. Working for an airline is a thankless job