Unfortunately, it doesn't work well since Fake!Moody in GoF could see Harry uder his cloak too.

Ya know...Jo could really have used a Panel of diehard canon freaks to beta the last book. It would have been an honor and we'd have shut our traps. Me? I'd have told her to nix the whole Hallows deal, and clarify wand magic. No one has yet to explain clearly to me why Lucius' wand (as yielded by Voldmort) didn't work against Harry.