I have been told that this is true in MW 1.6.10 or
older but not in
newer versions. Is this correct? If so, I don't understand the logic
in removing this functionality and would be interested in hearing why it
was done.
Before sending that email, I tested it with the latest version. I
tested it on a protected page, rather than restricting access to the
whole wiki, but I would expect the same behaviour regardless of the
method of stopping someone editing. Who told you the functionality had
been removed?