Re: FWD: I-D ACTION:draft-klensin-unicode-escapes-00.txt

one more caveat: protocol specifications need to specify this notation 
explicitly (either directly or by reference to the published RFC) if 
they are going to use it. conversely, this notation SHOULD NOT (maybe 
MUST NOT) be used unless it is part of the protocol specification.

one problem I see with introducing any new notation for characters is 
that it does create normalization issues by introducing additional ways 
to say the same thing.  e.g. after introducing this notation, "A" could 
also be expressed as \u0041 or \U00000041.  and it then becomes 
necessary to manage this conversion when copying fields from one 
protocol that supports the new notation (or in which it is benign) to 
another protocol that does not support the notation.

as an example of a potential source of problems, I'd hate to see this 
notation end up in X.509 certs.