I don't think it's unheard of for an airline to ask pilots for voluntary leaves during the "low" season. They have done that at my airline, too, even when we're making lots of money. Not that I think Virgin isn't in big trouble and there may be an ulterior motive, but that in and of itself might not indicate imminent failure IMO.

It will be interesting to see what happens when some decent hiring takes place over the next several months. Will they even be able to keep their pilots? If AMR, UAL/CAL, DAL, US, etc., wanted to shut Virgin down with some targeted hiring, they could if they wanted to be difficult.