Well as long as your not consciously aiming for the net man, your in the green IMO. If it just goes in their general direction they shouldn't get all ****y but if you actually pop one make sure your apology is sincere! Generally at higher levels both players will high tail it back so up the middle is the safest shot. Regarding players at net getting overheads back most of the time, at the collegiate level, I rarely see it on a well struck overhead (just getting a racquet on it and putting it in play are 2 different things).
"IF YA AIN'T REPPING 180 ON THE BAR BENCHING, YA WEAK!!! ARGHHHH ARGH ARGH!!!"
-Scrub frat boy