Y-Combinator needs a PR firm. That much is clear from the AirBnB fall out over the last few days, and I'm not talking about a PR firm to cheer lead for YC, or a PR firm to respond to this or any particular incident.
Instead, they need a PR firm that will evaluate risks of the evolving start-ups, in particular focusing on ones with lots of funding and press exposure. The firm's role would be to anticipate and plan for potential fall out. In times of trouble, the firm would be poised to jump in and coach the team on the appropriate way to respond to crisis in the public eye. A good PR firm would know that saying the word "funding" to the victim was simply not a good idea, and would have advised the founders as such before any meetings with the victim.
I think public relations is like a dirty word in the valley, but PR need not be an unethical or otherwise bad practice, and in this case, the right support would have made a world of difference. The firm really could just be an observer, except in times of crisis. It may be beneficial for the firm to interact with the start-ups, but I think this would at least lead to resistance, given the culture of technical-centric organizations. Simply having an impartial observer with a nose for media problems would avert some crises.