XMPP Message Carbons and OTR

[Koosha Khajehmoogahi]

Greetings,

The XEP-0280 (Message Carbons) specification states that some
particular messages could be excluded from being carbon copied by
having a <private/> tag in them.

While I am working on this XEP, I would like to know if there is any
use case for these "private" messages. One possible use case would be
OTR messages. Is there any other example?

The other thing to consider is how this thing should be implemented.
OTR is implemented by a plugin and not by the libpurple AFAIK.

Thanks.

-- 
Koosha