Remember they need to know which cell(s) you're within range of to get inbound calls to you. It's not like the networks send a message out via every cell tower

Remember they need to know which cell(s) you're within range of to get inbound calls to you. It's not like the networks send a message out via every cell tower on the planet asking if $rolandog{'mobile_number'} is listening every time you get a call or text. Whenever your phone is switched on, it regularly contacts the tower it's got the strongest signal from and says "Hi, it's rolandog's phone here, if you get a call for me, this is where I'm hanging out! kthxbye"