Look at
|/|artij||'s reply to Abubu. =|. |\/|artij|\| used the /me thing but instead of
* |\/|artij|\| bla bla bla
MyBB puts
* |/|artij|| bla bla bla
ie: without the backslashes ( \ ). I think it's a PHP bug. I think that the sames happens with /slap
edit:
the [post] tag seems to have the same bug (3rd word of this post). maybe the [thread]one too.