Even as a flying instructor I always do the first check of the day then follow up with a transit check after the student has finished fannying around.
I once found one of the planes which had been used for solo hire for a few days with less than 3 quarts of oil in it, and when I got it refilled it only had 4 litres of usable fuel in it which words were said about.
Also I find the pipers alot better for doing preflight checks, you can get a good look at the engine for oil leaks etc which you can't on the cessnas.
MJ