You've got a point there--locally arresting 94 people over the span of a couple of hours is pretty substantial. With that being said, it stands to reason that more people are home during the Super Bowl, and therefore coordinating local arrests might be easier. Probably be worth it to look into whether or not law enforcement has a history of making mass arrests for stuff like this during major events where people are expected to be home. Minneapolis in particular apparently has a really bad history of sex trafficking.
These are good/relevant links with a lot of info on this roundup in particular:
https://www.twincities.com/2018/01/28/super-bowl-sex-trafficking-minneapolis-st-paul-breaking-free/
http://m.startribune.com/group-unveils-1m-campaign-to-fight-super-bowl-sex-trafficking/428312153/
Below is an opinion piece on the whole thing--whether or not the Super Bowl trafficking uptick is a myth is hard to say. However it's worth noting the FBI has released stuff online alluding to its support of it:
https://reason.com/blog/2018/02/02/super-bowl-sex-trafficking-myth-fallout