Question on attachment defang??!

[Rob Poe]

I saw (somewhere) where they had a MailScanner chaning a double
extension from

bad file name example.reallybad.doc

to 

bad file name example.defanged-doc

so that the receiver would GET the message but would have to RENAME it
to actually run it .. instead of it getting stuck in the quarantine. 

Looked around in the documentation / faqs but didn't see anything about
it .. anyone have any good pointers?

thanks!