They can still lock the IEM or whatever it is on the phone. The sim just associates a certain phone number and sometimes settings/contact info with the phone, the phone itself still has an individual identity on the network, and if reported lost or stolen, they can lock the phone so that it cannot be used by anyone else.I dont see whats so funny, that would be shitty to have a stolen phone. Thank god for tmobile you just swap sim cards so I dont think you have to worry about not being able to activate it.