Likely cataloging IMSIs and IMEIs which would not constitute a wiretap. I know from experience these circles are concerned about roving protestors and agitators.
These sort of metrics can also be used with commercially available RTB data if and when cases go to court. I'm about 90% certain they ARE NOT intercepting phone calls and I'm 80% certain they're not intercepting sms
yes, ICE strike me as deeply and sincerely concerned about both agitators and bringing robust cases to courts :)