I have a flight on USAir that is serviced by regional jet. I notice that it says the carry-on limit is smaller for these flights, 19 X 15 X 11. I know the bins are smaller, but I wasn't planning on checking my average-size carry-on bag. I've flown on Delta's regional jets and never had this issue with smaller carry-on sizes, unless they've recently changed too. Anyone had this experience before? Is this enforced?