Cant view or submit Visitor messages in profile unless listed as a friend/contact

[mvigod]

As the title implies. Only show Visitor messages to those users who are accepted Friends of the user. Also can't submit messages unless the user is on the Friends list.

[ForumsMods]

There is an option in vbulletin in Edit Options:

You may limit the usage of your visitor messages to just moderators and your contacts. Limit usage of Visitor Messages to Contacts and Moderators