Yes, that is one possible solution. One of the overhead lockers makers is already demoing a locker with weight sensors and colored lights intended to be part o

Yes, that is one possible solution. One of the overhead lockers makers is already demoing a locker with weight sensors and colored lights intended to be part of a reservation system, where premium passengers or those paying a fee would get reserved space in specific locker locations. Of course, enforcement is hard. Airlines moving toward "basic economy" without access to lockers is becoming a thing -- and this can be enforced by making them board last and in a separate group, so the agents can check for big/multiple bags, and if a "basic" passenger does manage to cheat and find space, since they're last, they're not taking the space from a "paying customer" Airlines are moving toward an increasingly price-continuity model, where you can buy a ticket at whatever price feels acceptable to you, and there will always be another enhancement of upgrade available at a modest cost, pushing you to spend more to feel less discomfort.