The dark wizards in draynor chase way too far (~25 squares) and have a higher detection radius than normal. They bypassed the single target area mechanic when i had trapped one dark wizzy behind a tree, got aggro on the second one and then untrapped the first. Happy to demonstrate if needed.
i noticed even the gaurds will follow you too far. on real runescape, they are not allowed into the bank, let alone engage in combat inside the bank.