I have a MTB used for commuting, with slicks mounted on it. They are rated up to 100psi and are 26x1.25.

I have experienced many more flats with the pressure pushing 100 than when they are around 60. My reasoning is that when a rock is run over, the tires have no give, and puncture, whereas a lower pressure tire will give the rock some flex, and go around the rock and distribute its force rather than concentrating it. I may be wrong though!