Originally Posted by Often1

Focus on dimensions. I don't care if you want to bring a toaster or a change of clothes and I don't care if the container has wheels. All I care is that there are dimensions and that the item meets the dimensions.

Enforce it uniformly so that we stay away from the, "but I've carried this on 9 times in the past 2 weeks" crowd and even a so-called elite can learn.

Most people who can afford an air ticket can afford a measuring tape. Now, they can learn how to use it.