I always use polarized sunglasses when I'm at the pond anyway. So yes. It seems intuitive to me that you want to eliminate surface reflections so they don't skew your results. I think that may be why the readings are supposed to be taken midday, because if you're looking straight down you don't get a light bounce from angled, unpolarized light. When are we fishing? ;\)

Holding a redear sunfish is like running with scissors.