I thought Harald and I had reasonable examples of unsolicited return
controls (e.g., "search results not legally binding" and "shift-JIS
encoded") that made sense.
Hmmm... All that I got out of that was that if the client didn't understand
the Japanese control then it would be gibberish. Thus, the client could
safely ignore the control... Perhaps we need a new control on the Bind
operation that lists the Client's supported controls. Then, the server is
not allowed to send back any unsupported controls.