That doesn't mean that a handful of people with jail-broken cars are going to be able to get together and prove a manufacturing defect. If there were 2000 cars

That doesn't mean that a handful of people with jail-broken cars are going to be able to get together and prove a manufacturing defect. If there were 2000 cars that were jailbroken, and they all crashed in the same way due to the jailbreak.. don't you think they'd figure out that the jailbreak was the problem? It's not that hard to tell if the software has been changed from stock. If they all failed differently, and had different accidents in different scenarios, you're going to have a hard time proving a manufacturer defect.