>> It would be as accurate as the scale used.
It would also depend on the variance of the “tare weight” (the weight of the pigskin, completely empty) between football instances.
If the weight difference between a full and a partially deflated pigskin was “in the noise” of the variance in tare weight, then weighing the balls would not provide a meaningful measure of inflation pressure.
>> The only other accurate way to measure it would be to squeeze the ball, as inserting a gauge would inevitably cause some air to leak out.
I wonder if they could use a technique like the one where they test the pressure in your eyeball (sort of a “squeezing” test). They neither weigh your eyeball nor do they stick a needle in it — at least not at my optometrist’s office — yet they can measure small inflation pressure differences accurately.
As a side comment, once us engineer types get our meat hooks on a topic such as this, it goes from contentious controversy to boring snooze in less time than it took New England to score again and again and again, apparently :-)
It rained the whole game. I doubt weighing game-used (saturated) balls, and comparing the results to pre-game (dry) balls would do any good.