license categories, was: I'm not supposed to use the ECL v2?

[John Cowan]

Arnoud Engelfriet scripsit:

> The FSF's preferred statement says that the user has the option to
> apply any later version of the GPL to the work. The work is GPLv2
> until someone forks it and explicitly says he has elected the option
> to apply GPLv3. Then that fork becomes GPLv3.

Can you explain why this is not the same as explicit v2/v3 dual licensing?
It's generally understood that if something is licensed under the GPL
and the MPL, for example, that the licensee's powers are the union of
those given by the GPL and by the MPL.  A fortiori, it would seem to me
that given "v2 or later" software, you can do anything that either the
GPLv2 or the GPLv3 allows.

-- 
Knowledge studies others / Wisdom is self-known;      John Cowan
Muscle masters brothers / Self-mastery is bone;       cowan at ccil.org
Content need never borrow / Ambition wanders blind;   http://ccil.org/~cowan
Vitality cleaves to the marrow / Leaving death behind.    --Tao 33 (Bynner)