And just where did you get this 25%??????
Defense can be where ever they want, they just cant hinder the offense unless they have the ball or are in the act of fielding a batted ball. If they have the ball they can be anywhere they like and as has already been posted the NCAA rule is completely different.
I can tell you what the rule is for ASA but the umps do not follow it. In ASA the fielder must allow 25% access to any base, There fore no fielder is truly suppose to block the base. The play at the plate, The catcher can not set up blocking home plate before the ball is thrown.
1)If the catcher is in the process of going to get the ball and the runner and catcher hit each other than there is suppose to be NO CALL (incidental contact) Both players have the right to that spot.
2)If the catcher is stationery waiting for the throw then she who have to allow the 25% access to the pate.
3) If the catcher has the ball then she can stand where ever she wants