At that low of a PSI, you should be able to tell. Once the ball gets hard enough, it becomes much more difficult to tell. They’re discussing 11 vs 13. At 10 it’s pretty rigid. Even a basketball is only 8, and it’s larger and round. More rigid, is...more rigid.
Assuming the ball would survive, do you really think you could tell between an 11 and a 13 PSI volleyball by squeezing it with one hand? They’d both be rocks...and crushing isn’t exactly a normal volleyball motion.
“At that low of a PSI, you should be able to tell.”
I still doubt that he can tell to .1 psi. Besides, the volley ball will vary at playing conditions quite a bit more than .1 psi. He must be a very busy ref ...