Subpoenas have been used frequently for decades to request "records kept in the ordinary course of business". The only thing different in this case seems to be

Subpoenas have been used frequently for decades to request "records kept in the ordinary course of business". The only thing different in this case seems to be that there is a perpetual gag order. But if the local prosecutor subpoenas your phone records because you are being investigated for bribing an athletic coach at a university, I don't think the phone company will tell you about it.