Org-mode allows marking a set of tags as mutually exclusive. It also allows
the inheritance of tags.

(from now on I am talking only about these mutually exclusive tags)

When a tag is set in a parent, but also in a child, what I expect to happen
is that the child is not included in searches/selections with the parent
tag.

In the example [0], a search for black (e.g. C-/ m black <ret>) should not
match poodle, because it is white.

Now I realize that the mutually exclusive tag concept is probably only a
convenience for adding tags with C-c. And it doesn't seem to have any other
implications, but it would be nice to have. Do you think this is a
possibility or that I could get this behaviour some other way?

Thanks!

[0] http://paste.lisp.org/+76JF