The NCAA Women's crews never have a blarge! Why? Cause we get together and decide where the play happened (primary) and go with that. Too many times officials that have no business looking at a play come up with something that he/she should not have!
I remember a play from our regional (HS) semi final last year (I was watching it) and a "player control foul" occured at the free throw line. The center had a GREAT look at the play comes up with a the correct call, but here was the lead, looking 15 feet out from the baseline and calling a block (oh, BTW, he went to the state tourney 2 years ago). So the lesson here is; if you do have a double whistle, do NOT give a prelim signal. Get with your partner and decide. Might look bad for one of you (but you can always say you had the same thing) and get the call right!