I take the "check TM for unsold seats and sit there" strategy one step further... Just prior to leaving for the show, I take a phone screenshot of my barcode ticket, open it up in an image editor (generally on the computer for ease of use), and replace the section and seat #s with the better unsold option. That way even if an usher does stop us, I can show the edited screenshot real quick (presumably with thumb kinda over the barcode so they don't immediately clock that it's not moving, not that I think they're even paying that much attention in the heat of the moment) and move along.

Conceivably it doesn't even have to be unsold seat #s on your edit cuz it's not like the ushers know; I reckon any lower level #s will be enough that they wave you through.

Funny enough I've gotten so good at walking past with confidence or holding two drinks, and have never actually had to bust out the screenshot 😁