I really enjoyed reading this thread which brings back old memories. Having received my PPL, I was determined to go for a commercial. I lived in a small town in eastern Pennsylvania which had an aiport and a grass runway.
I rented the C172 on a clear blue day, but the night before had seen violent thunderstorms and about three inches of rain. This was an uncontrolled airport, but there was a guy in the building that took your flight plan. Actual ATC contact was PHL or ABE. I asked the fellow in the building if the runway was clear of contamination and he said yes.
Sometimes you get that itchy feeling that you should check it out yourself. I started from the takeoff point and walked the line. Right about V1 there were small puddles of water in the grass and 20 yards later there was a very large puddle -- 10 yards wide and 20 yards long. I decided there and then that despite the great weather, I would not be flying that day.
If I had followed the fellow's advice (he was not ATC by any means) I would have not been able to take off, stuck my nose gear in the mud/water, or had an accident -- probably not fatal.
Therefore, whether you're flying a B747 or a Piper Cub, it always pays off to check out the situation personally when any doubts arise.
LatviaCalling