You're asking for a rational explanation for a seemingly irrational action. I have no idea as to the viability of shareholder lawsuits in Great Britain. It's definitely a possibility that Party Gaming's actions precluded share holder lawsuits. I can guarantee that share holder lawsuits would result in the U.S. from a meltdown in price like the one Party Gaming had recently for U.S. companies. That's standard. Here's a link to a thread that discusses the rationale for Party's actions.
Reason for Pullout Thread