If the car is registered in a name other than hers, I'd tell the cop that is borrowing the car. Cops usually won't bust on out of state cars for tint.
If she does get pulled over for anything, have her drop ALL windows before the cop walks up. I have limo tint on my Camaro and I've been pulled over 5+ times for speeding (lead foot+ size 12 shoe) and the cop has never mentioned the tint.
