[Jtsummers]

Perhaps I was unclear, to add to my comment:

hinkley poses this as a fault in CQS, but CQS does not require your commands to always succeed. Command-Query Separation means your queries return values, but produce no effects, and your commands produce effects, but return no values. Nothing in that requires you to have a command which always succeeds or commands which don't make use of queries (queries cannot make use of commands, though). So a better question than what I originally posed:

My "Why would you do this?" is better expanded to: Why would you use CQS in a way that makes your system less secure (or safe or whatever) when CQS doesn't actually require that?