It would be a resource hog.
On a side note:
Bilal bhia, we were able to send private messages OVER the shoutbox before it was updated, but now we cannot send any PM over Shoutbox, we cannot report shouts, we cannot do anything because when we click on a member's name, it just opens the profile instead of opening the options to view profile, report that particular shout, and send PM over Shoutbox.