Did you ever figure out why everyone was able to use worldedit on your server? I just realized i had the same problem! please help :P
No, I havn't got that fixed yet, I keep disabling it when ever I don't use it(and hope no one else will figure it's on while it is).. if you get it fixed, please share with me as well. I did find out from the author that if one uses the Permissions plugin, worldedits own permission system are bypassed.