Absolutely. Also because they second they started this, they are already messing with some unique key aspects of fanfic, like the fact that there is a female dominated porn scene, that is not hampered by a male dominated publishing industry.
Crossovers are what happens when people let all the stories in their head freely connect. When you find those two characters from completely different universes that would have so much to say to each other.

If fanfic is caged by what you can and cannot write it loses a lot of it's appeal. Hardly any of my favorite stories would be allowed under their rules and in the end we would end with cheap tie in novels, which never could hold a candle to the better fanfics.