No because you can't make sure that the phone is of without removing the batteries which are glued in between sheets of glass.. 


Furthermore it could be remotely turned on again.  

 So the towers can triangulate you even when your phone is turned off, only if it’s not ACTUALLY turned off. I am understanding this correctly? 

 Yes. It might not actually be turned off even if the screen is „black“. 

 Additionally, take a look into apples find my network and googles equivalent. 

 What about it? Are you suggesting that Apple devices are en masse not fully turning off, for the sake of “Find my iPhone”?