Magic Duel · 10:27pm Dec 1st, 2012
My head canon is that Trixie initially sought the amulet to one-up Twilight, and everything she did after was under the influence of the amulet. I'm going to assume Trixie only had passing knowledge of the thing, and didn't know the risks. Furthermore, I think that she would never do what she did on her own. She's not a monster, after all. Just my two cents.
I took 'Magic Duel' as an allegory for drugs, personally.