No off-the-shelf software from Aruba is aimed at citywide location-tracking capabilities. You could write one, or you could sort of hack away with a tool not designed for the job, but if you're really going for surveillance you'd focus on getting better tooling.
So instead, they'll think of any tracking capabilities will be a handy added bonus. :) :(
And even if the primary purpose is their own internal needs, it's entirely possible for this system to track people the way the article mentions. Even if it isn't used, it's kind of creepy that they have the capability to do that, and that we can never really know for sure that they aren't.
That's not really how public safety people think. How useful would a mobile hotspot be during, say, the Boston marathon bombings, when cell service was inoperable? Most likely they'll have multiple systems with different capabilities.
And who gives fig what "public-safety" people think if it's old-fashioned? They need to step their game up and gladly join our Total Information Awareness world. I'm not paying the taxes I am for some sort of half-assed sort-of-oppressing oppression. Why did they compromise the telcos so thoroughly if not for this exact purpose?
Fascismo with no joy in wielding its ultimate authoritarian stick is nothing worthwhile for these US of As. Gotta give that 110%, idolators of power and authority for their own sake...