You could always restore to factory default, which in this case would set it back to an unactivated state. The kill switch would deactivate it plus require the same user to activate it.
Can anyone tell me how someone can sell an old iPhone to another individual with this new activation lock feature?
(Associate new iCloud account to an old phone?)
Wipe the phone and sell it.
Wipe - Activate - Sell?
the only way to put a true kill switch in is to have an electronic fuse on the CPU which can be blown by a direct connection to the cellular radio on a path that can not be disabled by software... so when the phone's id is flagged as stolen the CPU blows a kill fuse which makes it impossible to even turn the device on again because it blew a fuse at the chip silicon level...
It's a bit overkill if you just want to remotely shut it down if the phone has been temporarily misplaced though.