I recently flew a regional airline that had strict policies about bag weight (20 pounds or something). They had scales for luggage right there. Then I thought

I recently flew a regional airline that had strict policies about bag weight (20 pounds or something). They had scales for luggage right there. Then I thought to myself: the difference between my weight and anyone a few inches taller — regardless of fat — could be way more than 20 pounds, especially given some muscle. It makes little sense to inconvenience people by checking bags that are slightly over-weight, while standing next to someone that is probably twice the difference. Maybe, then, a rule for bags is also based on the distribution of weight in the overhead bins, as well as the difficulty of knowing exactly where the heavy bags would be. People are easy to identify and move, bags probably need to be more uniform. Plus, it would encourage relatively small bags (to help with the space issue).