I imagine you've thought of leaving their script to the very last so as to affect only them.

Maybe you could get MCA to write a callable KiXChecker to validate their script before you call it. Kludgy, I know, and you'd need to have some sort of revision tracking to avoid rechecking code that hadn't changed from the last time. Come to think of it, maybe Ruud could build that into KiX... something like a /Verify switch...

I'm starting to ramble... sort of cerebral diarrhea...