I'd rather install software and kill the phone myself rather than turn it over to the authorities. If they make a mistake - who's liable? Will it stop at theft or start being a judgment call, too? Authority has no common sense.
You can buy non-carrier branded phones - who's going to put the switch on them, especially if they are not bought in the US? You can use a GSM phone without a carrier if it has wifi. I have a couple I use that way - no SIM, no carrier control. I buy unlocked since I don't want to be hassled by the carrier's normal bloatware.