How effective will it be? Will this simply be an OS trigger, or will it trigger something on a lower level, like the bootloader?
AFAIK, on current Android devices, a lock can be removed if the device is wiped using recovery. Would this stop that? I know the data is the most important thing to wipe, but if the devices were turned completely inoperable then thieves would be left with no reason to rob people of their phones.
This will kill the legitimate 2nd hand handset market. With people selling their phones to buyers, then killing it out of spite.
It will specifically hurt the no-credit loan business where cellphones are often used as small lone collateral or collateral for pay-day advance loans. People won't want to loan on phones anymore for fear of users who loan them and fail to pay killing the phone out of spite.
What would actually happen: thiefs would soon get aware of this thing and would just power off phones and sell them for spare parts, etc. So in most cases you'll not see your phone back. On other hand, its very nice option to do all sorts of nasty things remotely on legitimate user in very nasty, privacy-breaking ways. So, more NSA spyware in your pocket, eh? I'm not going to buy this crap for me. Go to hell, NSA.