The next to last sentence should have read "and, we are not
obliged to carry that over to 3.x where cross-type ordering comparisons
are not the norm unless a type has specifically enabled them."

The gist of the idea is that in 2.x, we do have cross-type ordering
comparisons so we should make them as useful and non-misleading as
possible.  But, in 3.x there is no default cross-type ordering
comparisons so we're not obliged to return any answer at all.