This should prevent potential spamming by malicious members.
Alternatively, the people a person can messsage could be limited to those following them.
SixLinks Developers' response:
Good idea, will get implemented.
Tomo Says:SixLinks has changed a lot over its life. As good parents, the guys keep around the icons they couldn't use anymore in the icon pasture. (Actually, Jeff just agreed to this to keep Steve sane.)