That reminds me of how they changed Teamboat Springs' rules so that you now need a minimum of 4 people in a tube. For years, my parents and I would ride it, just the 3 of us. Then a couple years ago, my friend and I went to ride it, and had to wait 20 minutes for another group to come through the line. At first I thought it was a way to lower wait times, but the park was completely empty (it had been raining and was close to closing time).
I hadn't been to Blizzard in a few years, so I doubt this was a new policy, but I guess there's a safety reason in mind for both of these situations.