As far as i know, nobody will lifetime warranty Torque Wrenches, not even the major professional manufacturers. Snap On might have a 1 year, but im not sure. They'll send them out for calibration, but you'll likely have to pay depending on the dealer.
I only have a few Craftsman tools, and havent had a warranty claim denied yet, knock on wood. All my Craftsman tools are made in the USA, and I dont want to replace them with made in China crap. Ive read on some other sites that Craftsman and the others with "lifetime" warranties have begun to get tighter on returns, especially on cases of abuse (using non impacts on a impact gun for example). Ive seen this from Snap On and others. In my case Canadian Tire wont exchange for a complete ratchet, only give you a rebuild kit. A friend of mine had a claim denied because he used a pipe on a mastercraft (Canadian Tire) ratchet. I think in these tighter times, one of the things these companies are going to to save some cash is tighten up on warranties, for better or worse. Im sure they have some CYA language in those warranties to give them the right to deny converage.