- One person's casting ballot might be worth 6 times that of another.
- Extremist and "non-serious" parties might get some votes.
- er... Churchill!
I also find it hard to understand what "non-serious" means, unless it just means "anyone but the Big Three". Maybe the profs are worried about a massive swing for the Monster Raving Loony party.
Let's hope some serious political scientists are drafting a rebuttal.