My minimum time to be at the gate is dictated by what AA puts on the boarding pass as boarding time. It happens to be that this time is usually well into the boarding process these days, so I will often head over a little bit earlier - though one thing AA is pretty good at is protecting bin space for F and even MCE. Of course, I also am mindful of stuff like aircraft type and whether it is a regional or mainline. That said, if the OPs wife was truly there prior to the 15 minute cut off, she was IDB'd and should be paid compensation. I just don't see a reason to cut it that close, regardless of whether or not a bag is checked.