Guys, sometimes I stumble on something really simple that works for me...
I just used the "badwords" filter to specify that "script" and "iframe" are naughty words and I've never had a problem.
Of course, I don't have any boards where my members typically post any code, so the missing words have never posed a problem for my site. I suppose if my members started talking about a movie script they'd be surprised to see it as [censored] but that hasn't happened yet.
It would be kind of nice to just have scripting and iframes disabled though.
