@GirlCalledBlu A sandbox, in this case, would mean a game that is meant to cater largely to the people running it, and their friends/RP buddies' preferences.
An open, public game is just that. Its open to -everyone-, and should be run as such (to the best of staff's ability/as much as the theme of the game itself will allow).
If the theme of your game is so strictly enforced to be not just accepting of, but encouraging of IC behavior that is likely to drive people away from the game, or keep them from joining in the first place? Then you're running a sandbox advertising itself as an open game.
Mind, I don't knock either type of game, I've been part of both types... but the sandbox games were very clearly marked as such, with clear warnings that certain types of behavior would be prevalent, or at least common enough that not everyone may be interested in it.
Given that your advertisement says that its okay if you haven't seen the show, I suspect you mean to run an open game. HOWEVER, given how openly antagonistic the show is towards its own characters, you may want to caveat that the game has a higher than usual level of IC PVP/antagonism to be found. It can be shocking to someone new to a theme if they aren't prepared for what that theme entails. Lord knows it was a shock to me, especially since I'd had assurances that PVP was NOT being pushed on anyone, then immediately had every scene with at least one person deriding or maligning my character. Often for little more than offering a dissenting opinion from the popular one that seemed largely derived from OOC excitement to push the plot of the show forward quickly.