They don't have to be behind the center-court line...they simply cannot occupy the lane spaces...they must be behind the three point line and the free throw line extended...yet every time a T is called, the players automatically (for the most part) go stand at half-court...I can remember in my playing days (late 70's) that our coach always made us huddle with him while T shots were being taken - usually to chew me out for getting another one!!
