Again freedom of religion includes freedom FROM religion. And these nut jobs. The big difference is that sane people are willing to allow these people to believe what they want but they (religious extremists) are intolerant of others thinking differently from them.
You could get yourself a RF analyzer or an old Hammy (Ham radio enthusiast would likely have something you could borrow)and find out what they are using then that would allow you to figure out your options such as removing the antenna, sim card, or the module in some manner. The problem with removing modules could be they are tied into the cars electronic controller which could cause issues with the car even working.