You may not remember this, but aggy did something like that already, at DKR, in front of everyone pre-game one year.
They hid white spray-paint cans in their little corps-turds larp-stormtrooper costumes, and spray-painted some sort of junk on the Texas logo at the 50-yard line while hidden behind a wall of corps-turds so no one could see it unless there was a skycam at the game (there wasn't).
When they walked away, you saw the result, and the Texas athletic department managers ran out there after a couple minutes with spray-cans of burnt orange paint to cover over what the corps-turds had done.
IIRC, that was the last time aggy was allowed to do any pregame performance at DKR.
That might have been the same year that aggy and Texas ended their agreement to let each other's cannons travel to both stadiums to be fired, but if it wasn't the same year, it was around the same time that sportsmanship also stopped.
Speaking of petty, I knew one of their aggy band members (a dozen or so) that walked off the field during halftime for some commemoration performance (where both bands played together) that refused to perform on the same field with the Longhorn Band at DKR.
Their band director was furious, kicked them all out of the aggy band on the spot, and told them to find their own ways home.
The next day he told me he joined the little aggy stormtrooper corps (separate from the aggy band) because the corps leader hated the aggy band director and wanted to piss him off some more. Lulz.