As someone else commented upthread, I'm sure Belichick is pushing the boundaries of the rulebook in many ways constantly, including this item (QB selected pressure) that everyone does. He's always looking for any edge possible, call him Boring Al Davis or the Billy Beane that actually won something. I'm assuming he's still got people trying to crack opposing teams' signals and audibles to this day, though it'll be less effective since 1- teams are more careful to change their signals more often now and 2- The helmet with the green dot allows the bulk of the defensive playcall to be communicated directly.
The announced "checked two hours before the game and 5 minutes before the game" only makes sense to me if the Colts had alerted the league/officials prior to the game they were concerned about it being tampered with. It reads to me more likely a classic overly detailed lie to cover up they were sloppy. Per Rodgers, sloppiness on this is at the very least common enough to be unsurprising. If they were sloppy checking in the initial 2 hours pre-game window, is it more likely they'd admit to it when the boss comes asking or "Nuh uh! Not only did we test them exactly two hours ahead of time, we did it again just 5 minutes before the game to be sure!" With the stakes at play here I doubt the refs would own up to something like that, they already get downgraded and disallowed from plum postseason crews for the smallest shit. Why would they re-test when it isn't called for unless there was a concern already lodged? It sounds like a CYA embellishment.
And this is from someone who hates Belichick and the Pats, and as I noted previously, I consider Belichick a cold war era CIA station chief, he's *always* up to something. But I don't buy the reported refs' story (and sue me if I got the apostrophe wrong).