"Noise" is a technical term (as in "signal-to-noise ratio") that is now used in everyday speech to indicate the presence of incomplete or inaccurate information. In this context, I meant that some very good players are overlooked when the tryout invites are sent, while some less-than-stellar players make the cut (at least according to my son. But he added that everyone who was invited back for the second tryout was obviously very good).
For the Underclass tryouts it's pretty understandable: in general, kids in this age group have not been as thoroughly scouted as the rising seniors, so it would make sense to cast a wide net -- but there will still be some misses.