Just on a side note... people might want to know this... it seems there is no way to stop html from being displayed.
I did the following to the function bbcodeparser
just add in htmlentities($text) where you see $text.
Down side is you wont be able to use html, up side is you wont be able to use html. I am sure it is easy enough to add it to the interface so it is an option but it should probably be disabled by most people anyway as it could lead to some very bad security issues like users embeding another iframe and getting your sessions values which would then allow them act as you and administer the forums as they want which would be bad.
EDIT:
I edited this response to link to my response with the actual code change in it.
The code you need