Can't see visitor messages of some members

[Shinoi]

I don't know if this is a bug or something. I noticed it some time before, but I thought those members had visitors messages turned off. Then a few days ago Mastersarge posted on my profile and I couldn't answer him, because I can't see his profile wall. What I see is this:

Not just this, I noticed I can't see other profiles as well, for example LDX's, robinou's and so on. What's interesting is all those members joined after me.
It's not that I really care, I'm just curious and wanted to point it out.

[Mattbot]

I always thought it was a privacy setting like only people on your friends list can post on the board

[Shadowtime23]

I think it either has to do with the join date, post count, or you being on the friends lists of those members.

[Tyemdi]

This is really something either Oscar or Rezuth would know about. Best to ask them.

[Oscar]

It's probably some forum setting somewhere that has been enabled by misstake. I'm looking at it