Which is my point TGarza. This has become quite common over the last few years. But if OH space is common and on a first come first served basis, then whatever someone chooses to put in the OH bin should stay there and the person for whom no overhead space is available, should have their bag put under the seat or taken off the plane and gate checked.

That last point is where I think it goes wrong. The FAs don't want the hassle of telling someone their roll aboard will have to be gate checked and instead penalize the person who has a smaller bag in the overhead space. It is in fact a form of discrimination that favours those with bigger bags over those with smaller bags.

I think the reason we don't hear more about this is that the majority bring roll-ons and it is only a minority who travel with a smaller bag as a carry-on bag. Especially here on FT.

It's noticeable that in this thread, no one has tried to defend bigger bags getting OH space preference but instead have only made comments like, 'it's up to the FA to decide' or 'I've seen them move smaller bags' as you say. The question of whether this is right and fair or not has been avoided entirely.