I guess that's a rhetorical question.
Wisconsin statute does not allow a voter to register by party. These folks were really dumb, however. Wisconsin law allows registration at the polls -- that way, these folks would have voted before they were ever discovered. And our crooked Attorney General (now running for and about to be elected Governor) would have done NOTHING about it. Even if a poll worker noticed it, they cannot challenge at the polls. The crooks can still cast their ballots, and the State election committee and the AG will worry about it later.
Yes, you guessed it! Attorney General Jim Doyle is a DEMOCRAT!