Because the only thing they're teching is battery voltage and temp. Several people have been caught over voltage...so then people would tech, then hot swap (pun intended) a pack in...so now they're impounding teched cars I was told.
Edit: I was told (I could be wrong) they don't have an inductance meter, so stators can't be teched..and they haven't torn down any motors.
I personally don't think any of the top guys are cheating, but when you don't even have the tools to check, it's pretty enticing.