I'm willing to do a lot to facilitate on on-time departure and quick disembarkation. I frequently help people lift their hand luggage and retrieve it after landing. It's courteous and helps keep things moving.

As far as checking my own bag--I guess I'd see that on a case-by-base basis. I often limit my hand luggage anyway. It's easier on my shoulders and arms!

The European carriers are vicious about hand luggage. I don't know if we really need their level of strictness, but I certainly see the point.