I wonder what kinds of techniques, if any, these virtual cell phones employ to evade being discovered. You would suspect that they could be discovered through triangulation.

Two possibilities:

1. Most if not all of these virtual cell phones are connecting from the same location.

2. Some of these virtual cell phones are connecting from the same location, with the remainder in reserve.

In the case of (1), you have both a fixed location and a high saturation that is unlikely.

In the case of (2), you could imagine using certain numbers at certain times to simulate the work day or hours during which people are more likely to be at home. Randomization or round robin could produce unlikely patterns, but without them, these virtual phones would be underutilized, save for some kind of cyberattack that would compromise their location.

Or the truth simply may be that they aren't doing anything, because no one is watching.