The risk with checking the inbound aircraft is that, if you are at an AA hub or even focus city, they could always do an equipment sub with something that's there. For this reason, I always stay close to my gate in those cases. I will also check the AA app for inbound flight info in the cases where an equipment sub is 99.9% improbable.
right, if you're boarding in 15 minutes and AA shows no delays but Flight Aware shows your incoming flight is still 30 minutes away from landing. I'd believe the AA app as an equipment change is definitely a thing.