Good idea on their part, they'll have their hands full either way, Even with school out for the summer at UW. Should Barrett win, and if you're a conservative don't think that isn't still possible, Madison will erupt in celebration. If Walker wins, I really don't know what to expect.
My gut tells me election night would be one of relatively quiet shock and denial. I'm guessing it'd take a day or so for the anger stage to set in. I could be wrong though, I really don't know what to expect from the left if Walker wins, in terms of immediate response. Long term response will be to discredit what they cannot defeat, just as they did with Ziegler, Gableman and Prosser.
Here's something to consider, I know what the conservative reaction will be, either way; subdued. Yes, there is the exception here and there on the conservative side, but throughout this year and a half, for the most part, they have been the adult in the room. Whatever happens Tuesday, I expect that will still be the case.