It is the responsibility of the pilot to assure that the runway proposed for use is suitable, aircraft type, and conditions considered. Information from "the ground" can be helpful, though sometimes has originated from a source which may be more enthusiastic, than formally familiar. The pressure a pilot might feel to "get to the event" can be an influence in decision making, but, at the end, it it still the pilot's responsibility go operate the aircraft safely, and within any limitations. It is correct that generally, there is little to no performance data for GA aircraft for unusual grass or very wet runways. That does not prevent operation from these surfaces, but certainly imposes upon the pilot an added layer of decision making, perhaps with less than ideal data with which to make that decision. Then, the familiarizing ends up happening in a small, congested area. Would the pilot take that aircraft and practice on a waterlogged runway just to gain skill? For myself, a waterlogged runway is a big AVOID for most aircraft types I fly, as the water spray/splash from the nosewheel into the prop(s), can be very damaging to the prop(s). Though not as damaging as losing control of the plane could be! Sometimes, saying "not today" is the decision which is better in the big picture.....