I boarded a flight "late" recently (meaning I didn't board with Zone 1) and the first thing the F/A said was, THAT bag needs to be checked...there is NO room"...I said very nicely, "good evening. i am seated in first class. is there any room there?" She apologized and I found space. I just wish some people would say, "Hello. Where are you seated? ok, you are in coach, we need to check that bag."
also, If my bag ends up a few rows back, no biggie (unless I am on a tight connection and then I would hope I would try to board first)--and these people who are so nervous about their laptops...do people really walkoff with someone's laptop???? Or, how about the, don't squish that bag in there, my laptop is in there...what's it made of feathers?
It happened to me once. The other guy made an honest mistake, but if I had not noticed, it might have been a while before I got my laptop back.
Squishing is one thing, but when someone does the cram and jam routine to squeeze a bag in, it is possible to damage a laptop. The padding is designed for normal usage, not Mr. Strongman Toobigcarryon.