We do clear everyone pretty much to land on first contact (I won't go into the good or the bad of it as I have intersting discussions with some of my brethern here <G>.), we also know that we are responsible and can tell folks to go around. As to the contact ground point nine on clearning, all grounds in the US are 121. something unless otherwise noted. That is one way of getting around the whole thing... If you don't understand though, just simply ask on freq.
regards
Scott