[EricH]

Originally Posted by Nimmy

but isnt the fact that it is incidental incursion afect the penalty decision?
I mean maybe 'only allowed 3" in if they are infact pushing balls in'?

You seem to have done your homework here. You are allowed incidental-- not intentional--incursion up to 3 inches. If the incursion is intentional, or greater that 3 inches (about 6.5 cm for those who aren't used to the Engish system), it's a 5 point penalty.