USSSA, Bat Stinger

[Bandit]

Could someone please refer me to the USSSA ruling that prevents players from having a so called "bat stinger" on the knob of the bat. My daughter has one. It does not compromise the 90 degree angle of the knob, it does not "alter" the bat. I have no problem with her not using it I just cannot find the rule the umpire is speaking of. And with the # of rules these guys are "adjusting" as I was told on at least two other occasions tonight I'm sorta believing this might be another one of their "adjustments". I've done a lot of umpiring and have yet to "adjust" the rules.