I've got one for you that will make you feel better... this happened to one of my best friends in early 2013.
So My buddy left his keys inside of the center console of his brand new 2012 Chevy Silverado. Why he did this make the story too long and overall not important. His truck was parked in his driveway, and it just so happened that a group of thugs decided to make a run down his street breaking in to all of the cars.
My buddy woke up the next morning, and noticed the window of the car across the street was shattered all over the street. he then looks in his driveway, and his truck... GONE. You can imagine the look on the thief's face when he breaks into the truck and finds the keys right in the console. And it also just so happens that my buddy works in the construction industry, so the back of his truck was filled with just about every tool that he owned (truck had a camper shell). And to top it off, he had all of his hunting gear in the cab of his truck... knives, binoculars, etc etc. And under his seat, he had a 9mm pistol. All of it... GONE.
About 8 months later (after he bought a new truck and replaced everything), the police called and had found his truck, totaled, bullet holes in the tailgate. In a separate phone call, the police informed him they had found his gun... as part of a murder investigation in which the gun was used, and told him he could get his gun back after the trial was over.
Makes losing your backpack seem kind of insignificant in comparison doesn't it.