I have had AM weigh my hand luggage at check-in. I have seen AM wander around the gate area looking for potentially offending bags. I have seen AM weigh hand luggage at the gate. I've taken my laptop out in a manner that they don't see it prior to putting it on the scale for a tag at check-in (when I've got checked luggage) as to avoid weight issues. I have only flown AM in the front cabina (and many times) and have no confidence until I'm onboard that I won't have an issue, unless there's a current hand luggage tag affixed to the bag. I've actually had them rip off the old tag and place a new one on.