Minnesota DFL's underhanded fund-raising at State Fair

I just found out about this. The DFL is selling mini-donuts at the Minnesota State Fair to raise funds, but they are deliberately hiding the fact that they are running the booth. Here's a copy of the letter they sent out to workers:

(Click to enlarge.)

What a bunch of weasels! I doubt contacting the DFL will do any good, so instead, contact the people at the State Fair in charge of concessions/exhibits at (651) 288-4456. One thing I'm wondering, too, is if it is legal to raise political funds without letting people know to whom they are going.