Undoubtedly. Being a solid 61er, I have heard stories of people failing rides at certain schools by being slightly off center line on taxi, or taxiing too fast. I taxied too fast on my Private ride and was simply told "slow down" because of x, y, and z (that ride was was done with a hard-ass DE: I thought I had failed, but passed. Didn't feel good about it though). On that particular ride I was stressed out came out on top. As I learned more and thought about it more he was doing just that: stressing me out. I didn't fail to perform a task outside of the PTS. That being said, hearing of students and pilots getting busted over trivial matters that should simply be reminders to enhance safety, is disheartening. Not everyone is going to have a perfect flight, part of flying is human error and sometimes we need a DPE to remind us.
Not starting a 61 vs. 141 debate, but its seems like there are some hard-ass DPE's screwing with peoples careers at those schools from what I have heard. Could be coffee pot FBO talk from all I know.