I don't know much about this app...or cell phones. But perhaps your suspicion is why the program is only being offered on cell phones & not computers? I assume 1 requirement whenever FARs are issued for drone use is that you'll need a live-functioning phone turned ON whenever you're operating a drone?

Could be....maybe.

But, to me, in reality, unless the Feds (aka FAA folks) have hired about 100,000 employees in the last few months, there is no way they have enough spare people to drive around "pinging" towers to see who/where drones are flying. They became amazingly understaffed many years ago. The aviation weather & flight planning people used to be FAA, but it was given out to private contractors. Flight & written tests for general aviation & airline folks used to be all administered by FAA employees. Now it's mostly handled by ordinary citizens granted the title of "flight examiner". Airlines conduct their own training & flight checks. Occasionally an FAA person may observe, but only very occasionally. Anyway, all those private sector people may work in aviation, but they get paid by a private company that has been contracted (after bidding) by the FAA. If the registration is/was free, then will move to a whopping $5...I don't see the FAA budget allowing much to hire snoopers to monitor drones.

Now....there may be some FAA person at a large public gathering that often seems conducive to "aerial viewing" that will monitor for that occasion, but keep in mind, this is nothing new. If a temporary flight restriction (or permanent) was set over an area, such  as a superbowl football game, then it could be monitored by FAA folks for that short term of existence, which may only be a day.

I'm guessing this drone thing is small potatoes on the FAAs daily list of things to do, though some of the public thinks it's only second to FAA airline scrutiny.