This has been a longtime bug, but I've never brought it here. I once had both my PMs and VMs set to contacts only. However, when I changed back it back, and I sent a VM to someone who wasn't on my contacts / friends list, they sent me a PM reporting that could not VM me. I don't mind having to send an invitation to someone if I want to make a comment or anything, but for some people, it seems to be hassle. It seems that some people also experienced this on SEGA Forum quite a while back, and they tried to fix it, but couldn't, so I don't think it's a bug specific to this forum, but is there a possible fix? I'm going to guess a vBulletin bug for the time being.