I'm writing a module that should hide user existence according to their privacy settings.
I've been able to hide names (overriding phptemplate_username) and users profiles (404 with hook_user view). That's far from clean but at least it works. Is D7 any better in this area?
But I'm out of reasonably clean hack to hide users existence in user_autocomplete.
Everything is guarded by a user_access, 'access user profiles' and I can't see any other way than hacking core.