People forget that the purpose of the Teen Grid was not only to keep teenage users from accessing "adult" content. It was also to keep adult predators from accessing teenage users. Hence the extensive background checks required of adults wishing to go onto the TG.

If the two Grids are merged, this protection goes away. Does LL no longer consider this important? I can imagine the field day the press will have when there's an assault on a teenager as a result of that teenager having met an adult predator in SL. LL doesn't need that kind of bad press, any more than they did when they set up the TG in the first place.