A few years ago, it actually went too far here in MN--the insurance companies were being paid enough for these repairs that, to gain a competitve advantage against other glass repairers, they were offering and advertising kickbacks to customers. Typical ones were a box of steaks, $50 restaurant gift certificates, etc. Needless to say, the potential for fraud was rampant--"Honey, we're out of steak, and I want to barbecue this weekend. Go throw a hammer through your windshield."
The legislature eventually put an end to it--but of course they did it the wrong way. Instead of requiring insurance companies to stop paying such exhorbitant rates for glass coverage to the repair companies (and requiring the savings to be reflected in customer premiums), they simply declared that the glass repair places are required to keep all the money they receive from the insurance companies--they're not allowed to give it away to their customers.