I always thought the reason was so the scorer's table could see you during the free throws, to implicate whether or not the basket was good, say a lane violation or not... so I have no freakin clue...personally I like it because the coach can't grip at me about the call, so I won't have to T him up... even though I may actually have to T him up if he starts yellin across the court at me during the free-throw...
WAIT! Did I say may? I meant I
WILL T him up when he starts yellin across the court... hehehe