True, but using override clearly documents what you doing in that class. Otherwise you have to arse about looking through the interfaces to see if an unmarked function is an implementation, which is the same end result as unmarked overrides.I vote for requiring override in all cases; I think it makes things clearer. YMMV.
I guess that could be a custom annotation/attribute (if that's going to come sometime) so it doesn't pollute the language.
