Just my opinion, but I believe this was probably initiated by a lawyer looking for a huge cut of any settlement, as opposed to a herd of disgruntled employees walking in to a lawyers office.
As our civil litigation system becomes more Americanized, lawyers are getting friskier and riskier, heck just check out some of their advertising. I'm not saying the whole thing is with or without merit, I'm just giving my opinion as to who I think inititated it.
And I agree, if any likely settlement is too huge, they'll just pack up and restart as someone else.