It's probably not that they know something. I imagine they already have these agreements in place in case of any calamity (natural disasters, civil unrest etc) to rescue british nationals. The gov is eerily quiet about it at the moment, but I imagine there need to be rescue flights at some point as none of these countries will want to keep foreign nationals within their borders for longer than they have to. I'm chatting out of my arse though, I have friends abroad which I hope will be repatriated sooner rather than later.
Even if they do run these flights, they won't be anywhere near enough movements to sustain the business. I don't imagine they need more than 5% of their capacity to organise these flights.