Yup, my 04.5 had an aftermarket alarm installed before my purchase, and I elected to purchase it at the time of the sale. BUT it failed on me and I couldn't start the truck, had to have it towed to a dealer, not the selling dealer, and not knowing it was the alarm locking out the ignition. The dealer charged me $80.00 just to tell me they found it to be the Alarm and bypassed it until I could get it back to the original dealer.
The worst part was the tow truck driver was going to bumper pull it and had it on the lift ready to tow it. "Hey, it's a 4X4, I exclaimed, don't you need to have all four tires off the ground?" and he agreed with me and set up the tow dolly for the rear tires. If my wife had been the one that it happened to, he would of towed from the front only.