Ahh, well then I can say thats uneducated for sure. Definitely a lot of newbies think a shirt will instantly boost your bench 100-200+ pounds, which is bullshit. If you dont have the triceps, you wont push it up.
I didn't get to train in my shirt a whole lot before I lost my training partner, but it didn't do much for my numbers honestly. It was just a single ply trainer, but it still could have been worth more if I had the tricep strength for it. I already forget if it was injuries or losing my training partner that came first, I was doing some high volume shit and that was hard on my body.
I also got hurt once when some cough *asshole* cough spotter tried to show off by shrugging the weight up as quickly as he could, when I was board pressing. Fucking prick showoff. Unloading the weight that quickly fucked me up for at least a few days.