Board Thread:Show-Related Questions and Answers/@comment-27094327-20151019041819/@comment-27094327-20151020022725

Yes on the first two. As for the second...on the one hand, the sword might be enchanted to kill magic-users, which is presumably Arthur's reasoning. On the other hand, attacking someone with their own magic is usually a recipe for disaster. See, e.g.: Severus Snape (Harry Potter), Gellick (Deltora Quest), etc.