Where is this rule?

[dsimp8]

An umpiring colleague of mine asked me to post this and get some feedback. He does not have internet access so I told him that I could find the answer here.

Situation:
High School Varsity game

Bottom of the 1st inning-

The leadoff batter comes up to the plate and asks for time to "dig in".The PU gives her "time" and proceeds to wait until she is done. The girl steps into the box and the PU yells "Dead Ball!Strike one on the batter!" The coach comes unglued and wants to know what she did to warrant the strike. The PU tells the coach that the batter covered up (or erased) the front line of the batters box. The coach says "That's not illegal." The PU said she could only mark out a portion of the line and not the whole thing. The coach asked him where in the rule book the rule was and the PU said "It's in there. Play ball!!"

Now before I go any further, this umpire has been caling for about40 years and has a knack for letting his presence be known at the games he is calling by a)showing up a player that he knows or knows one of their parents b)giving the players gum c)making routine calls into a side show by pointing continuously at the base before making the call.

The coach knew this and told him that he did not have to do this to "announce he was there".From what I understand the coach is going to request that he not call anymore of their games since he gets it inside the players' heads that he is calling the game.

The umpire that requested I post this was the BU in this game and he said he had never heard of the rule but that he was not going to go against his partner.

Can ANYONE tell me where this is is a rulebook (NFHS or ASA) becuase we have spent the morning looking for it.