We're not talking the type of crashing you'd normally associate with WipEout, this is far more frustrating. Since the European PSN Store was updated earlier today we've been hearing reports of people experiencing crashes and game freezing whilst playing WipEout HD. Members of the official European PlayStation forums think they might have the answer. It seems to only be happening to the more sociable PSN users; those with over fifty friends in their friends lists.
There's no word on a fix, other than signing out of the PlayStation Network while you're playing. Obviously, this will prevent you from playing online. PlayStation Forum moderators are looking into the issue as a matter of urgency and hopefully we'll see a solution soon. We've experienced the freezing ourselves (and yes, our friends list is massive, thanks for asking), but an official cause hasn't been confirmed by anything other than anecdotal evidence at this stage.
[Thanks to everyone who sent this in]