I went to the fruit and veggie market the other day and went over board....lol. Had to buy a pineapple amongst other heavy things........well I crammed my PC bag with most of the bags, and it was heavy!! It held up! WooHoo, so maybe there was just a bad batch of bags, but most of them are tough!
Hmm, I never had a problem with my bags. I love that they hold so much more than the plastic grocery bags. My problem is remembering to bring them in the store with me!
I haven't had trouble w/ mine either. I, like you, do not go easy on my bags! I fill my bags w/ non-pc items that recruits would need when they get started- pens, highlighters, index cards, calculator, etc. My recruits love them!
I have found that if you get a sharp corner then it can tear. One of mine has a rip in it from a corner of a box