In a perfect world, BFan is correct. A conference should not book two conference tournaments in the same city for the same weekend. However, we know the caveat is that WCHA and Big Ten are different conferences. Should they have communicated? Maybe, but they are probably relying on the host school being able to support THEIR tournament, after all....the host school presumably submitted a bid. It's quite possible that the Gophers were in the "we'll take what we can get, just let us host" type of mentality.
As others have said, when it's all said and done, I don't think it will impact the attendance too much. So perfect world yes, they would be staggered. But still probably not a huge deal.