Have you ever bought a site, and then a few days/weeks/months/years later you get contacted by an authority that makes you remove your site or something? If you bought that site what would you do? If you sold it to someone else would you have to refund them or what?
Once the site transfers owners, the new owner is responsible for everything. Unless you were lied to or defrauded and you have it in writing, it is your responsibility. If i sold you a car, and it was broken into, i'm surely not going to pay for the damage.