Window Tinting Question

[SvXit]

Okay kids, this is a long one and has nothing to do with the SVX per se, but should apply to all cars in general.

Yesterday I took my Audi to a shop in Maryland to get the windows tinted. They did the SVX about four years ago and it has held up well, usually getting compliments at Reading and a few other meets. N E Ways, I took the Audi to them for a 45% tint all around. Weather was sunny when I dropped it off. When I came back to pick up the car, it was raining. They were still working on it and I saw a guy tracing the outer edges of the rear window with a heat gun. 15 minutes later the car was pulled out of the garage. I looked it over (looked absolutely gorgeous), paid the guys and headed out.

About three hours later when I go to the garage to drive the car somewhere and look everything over again, there is a six inch crack in the back window! There were no impact marks whatsoever, and as I drag my fingernail across the crack, I can feel a slight elevation. Today it turned and grew another 7 inches or so.

So then, having said all that, here are my questions: Has this ever happened to any of you? What I am trying to figure out is basically how shops that tint windows handle things like this. I am thinking that they will try to say it was my fault somehow and that it basically sucks to be me. When I picked the car up, they said that there is a lifetime warranty on the work, but there was nothing mentioned (and nothing on the receipt) about dealing with a cracked window. This can end up costing close to 1K to replace, so when I take the car to them tomorrow morning, I am bracing myself for all sorts of 'it wadn't me's', but I just wanted to try to be prepared before walking in there. Any of you encountered this before? Thanks in advance for any help!