So she did not notice the IT guy stop by, grab her personal cell phone, and install some sort of data app. She was flabbergasted when he handed it back to her.
I'm rather surprised that your co-worker's phone was out where the IT guy could get to it. Mine would have been in my purse, or perhaps a desk drawer if I were expecting some sort of emergency call. If I were a supervisor I would look askance at anyone who had their personal phone laying around during work hours. Perhaps that would make me a mean boss. Was co-worker listening to music on the thing while the IT guy was messing with it? Is that possible?
That being said, I think that the IT guy was quite rude and outrageous to take the phone without asking. I do wonder, though, if he was actually told to get the app on everyone's phone, and was just trying to follow his orders.
I feel very strongly about the right of privacy. I'd be tempted to change phones even, in case the app couldn't be fully removed, and the company was still tracking my stuff somehow. Probably I've just seen too many movies, and am attributing super powers to computers and IT departments.