Meh, reading the whole thread before voting could help sometimes...
The first option - making tweak available for everybody - is a definite no for me. Demo players already have one of the greatest demos ever made in the history of games, it's almost a full game with unlimited playing time. If you want to have new content as a demo racer think about buying the game first, that's a lot of new content for you. And every single demo racer on this forums who wanted to get S1/S2 managed to get it, so the argument "but my dad won't let me" and similar ones won't work. If you can be adult in such matters you usually can get what you want. This is mainly directed at a certain demo racer in this thread.
I can see the point of prohibiting a release too, but in my opinion it would be better to have one "proper" tweak application, with license check and cheat protection (see hotlaps) instead of having fishy releases somewhere scattered over the internet.
The "moderated mods" aren't exactly what I would want too, since it's in my nature to rather create stuff from scratch instead of having a pre-made solution. On the other hand you wouldn't get tons of lousy tweak presets then.
Guess I'll stick to my vote (release to licensed racers) after all
