"individual phones actually *poll* towers every few seconds"
I highly doubt that. A 2G gsm phone left next to an audio cable will only generate the familiar "bidibip" noise once an hour or so. I assume it does that in response to an "are you still there" request from the tower.
The radio transmitter in a cellphone is about one watt. For battery lifetime, you really don't want the transmitter to activate every few seconds.