Can Headlight Protection Film Cause Lens Cracking?

No, a headlight protection kit is not going to cause the polycarbonate / Lexan to fail

What you have seen and heard / been told has nothing at all to do with the headlight protection kit. Polycarbonate & Lexan, what most composite headlights are made from these days have a continuous working temperature of between 248 - 475 F, depending on the formulation. This means that water would boil instantly upon contact and that you would get a nasty burn if you touched them before they reached the failure point. The materials we use in our lighting protection kits have been tested to 225 F, significantly lower than what a headlight would fail at.

Polycarbonate lens failure is usually a manufacturing issue during the production of the polycarbonate, or a chemical contact issue. The latter could have occurred before you even picked up your car from the dealer. There is one dealer here in Dallas who had to replace a lot of headlights when it was discovered that the (outsourced) make ready / wash people were using wheel acid on the entire front of the vehicle to make bug removal easier... There is a long list of chemicals that the polycarbonate lens is susceptible to.

Unprotected Headlight with Crazing

In the past early S2000, C6 Corvette, and early 350Z owners reported some hairline cracking of the headlight lens – even without any protection applied. Most likely a chemical interaction or an OEM materials / manufacturing issue. A headlight protection kit is not going to cause failure of the polycarbonate…