My reality is that I rarely bring a bag like that, my carryon used always be my Think Tank roller camera bag that was designed to fit in the overhead and since it was filled with fragile, expensive gear I always made sure it was going to fit. Now that I am retired and just travel with a shoulder camera bag I made the mistake once and got caught. I was more annoyed by the attitude of the gate agent and the reality of seeing so many others carrying on so much other stuff.