Stretching a bit the burglary analogy you could put it like: "imagine a guy selling you a door lock that can be opened by anyone and then you use it to lock a s

Stretching a bit the burglary analogy you could put it like: "imagine a guy selling you a door lock that can be opened by anyone and then you use it to lock a shootgun, can you shift all the blame to the guy who just took it an shoot your neighbor?"