202 in current implementation

Dave,
As you mentionned that you know implementations using 202, do you know 
what is their behaviour when there is an unmet mustUnderstand?
(sending back the mU fault instead of a 202, or is it completely hidden)
Also, do all implementations you know do the same?
Thanks,

-- 
Yves Lafon - W3C
"Baroula que barouleras, au tiéu toujou t'entourneras."