The ESRB just re-rated Elder Scrolls IV: Oblivion from Teen to Mature. On the surface the bad news for Bethesda is that fewer units will be sold to an M audience and it's a little bit of a black eye as well because of the "nude content introduced into the game from a third party mod". Sure, it's only for the PC version but the news blurb will affect all SKUs regardless.
Ok, so the story is that there was no nude content in the game's data but some modder added it with a utility. In the case of GTA's Hot Coffee incident there was actually some hidden art assets and animations that were unlocked by modders and thus got that game jacked up by the ESRB as well - and it really affected ALL ratings in the industry past that point. It's now harder to get a lower rating because of these hacks.
What's the point of this all this? That modders are now screwing up the industry they're supposed to be helping. In 1993 we opened up all our data to the industrious and ambitious folks out there who want to see what it's like to be able to make their favorite game a little more like what they'd want.....and get a taste of being a semi-game designer in the process. The most awesome example of what this philosophy has brought is CounterStrike.
Now what's going to happen? You'll probably start seeing game data files becoming encrypted and the open door on assets getting slammed shut just to keep modders from financially screwing the company they should be helping. And the day a game company's file encryption is hacked to add porn and the case goes to the ESRB for review - that's when we'll see how well game companies are protected from these antics and what the courts will rule. Hopefully it'll be on the developer's side.