actually when you think about it she could just send him to the moon if she wanted to

Well, I beg to differ. Celestia could sent Nightmare Moon to the Moon, because she HAD the Elements of Harmony. It was a one time thing. She does explain in the seson two opening, that she and Luna are no longer connected to the Elements anymore, since the Mane six has their power now. Therefore sending somepony to the Moon is beyond Celestia's capabilities. Or at least, that's what she says, the "official" version. Maybe she still has that power, just hides it, who knows? Anyways, according to the rules of the Internet, Celestia is greater than Chuck Norris.

Why isn´t BEER an option?