Dear in my site i'd put limitations to new registered user as that user gets by default label "Pn.Vrf." {pending verification} which label have restricted permissions to access site in this case a user registered and he posted comment on newsfeed with out having permissions to do so. go through attachments for detail {also raised some what similar issue that why default profile should be editable click here on this link http://www.oxwall.org/forum/topic/4591?page=1#post-21298 }