I am not the slightest bit surprised to hear the airplane in question was flown a 100 hours with the oil pressure reading too high. One of the things I find rather discouraging is that there seems to be a significant problem with the culture in flying schools and clubs. It is IMO the toxic combination of pilots not making the effort to learn their airplane systems combined with a willingness to accept broken airplanes without complaint. Sadly it starts with instructors not doing their job
2 examples
1) A while ago I was asked to do a couple of flight instructor ratings for a local school. On the first flight in the C 150 I let the student do the takeoff and gets us to the practice area so we could start with learning how to teach Attitudes and Movements. On the way out I thought the student was doing a very good job of staying coordinated. When I took over I found out part of the problem, as soon as I let go of the controls the airplane turned sideways. In 30 years I had never seen an airplane so badly out of rig. When we got back to the school I asked the engineer what was up and she said in the year she had been there no one had ever complained
. After she went through the airplane and adjusted all the control surfaces the airplane flew perfectly hands off
2) A different school and another C 150. I was asked to fill in for a sick instructor. We go out and the engine seems a bit rough on runup. The student apples full power and it is immediately obvious we are a good 100 RPM low on the required minimum static RPM so I take over reject the takeoff and taxi back. When I explain why we rejected he says "What's static RPM ? "
. I snag the airplane and t turns out one cylinder has an exhaust valve that was probably only a few hours from total failure. As I am leaving the dispatcher says "Oh the instructors have been complaining that that airplane has been really doggy for weeks ! "
Bottom line learning your airplane systems is a choice.You can make the effort to really understands how things work so you know when things are not doing what they are supposed to do.....or not,and then make good decisions.