infield fly

[Topshelf1227]

ASA rules high school softball...

when the infield fly is in effect, as soon as it is called can the runners run? There seems to be a disagreement on this in that on e belief is that after the infield fly is ruled, if the ball is then caught, the runner can be doubled up if they aren't on the base. The other opinion is that once the infield fly is called, it is assumed a catch has been made and the runners can advance (as soon as the call of infield fly is made, they don't have to wait until the ball is actually caught or not) with liability of being put out. Is it true that if a runner leaves second as soon as the infield fly is called they can be called out for leaving the base before the "catch"?