IP address locators as target points.
Simple triangulation from cell towers for those that have the applicable equipment.
Error rate/distance of a few hundred yards though.
So significant collateral damage to be expected.
Yes.
Physical emitting trackers are lighter than a coconut even if the airspeed velocity of a African Swallow would allow more ounces than what was in the pagers.
However, in addition to basic triangulation, lookup Stingray or Harris cell phone trackers.