). I just want to make sure the other airports aren't going to measure every time. I just carry it on. It they hand me a yellow tag I figure the plane is on the small side and they put it underneath for that leg of the flight. If they don't I assume it will fit in the overhead. 
If you are chosen at random to have your bag measured and the bag is even slightly larger than the maximum permitted measurements, you may have a problem.
Once we were at AC's gate out came the purses again no problem.
Beware of the differences between airports and airlines on what is the acceptable number of carryon items too, not just the size.
In May my airline (Air Canada) accepted, as listed on their website, the roller bag, a second over the shoulder bag, within a certain size, AND a purse/diaper bag etc. Had no problem leaving Halifax. On the return trip, out of Tampa, there was security standing at the enterance to the gates not allowing us past them until we had somehow managed to shove our purses into one of the carryons! You can imagine how easy THAT was!
This incident will definitly figure into my packing plans for next time!
I have seen Air Tran out of DFW measure bags (both carry on and checked bags) several times. They do stand the bag up and measure from the top of the handle to the floor (so including wheels, as well as handles), they then measure width (again including any handles or pockets), then measure the depth. They include all wheels, handles, pockets, and any buldges when they measure.
