[License-discuss] Permissive but anti-patent license

[Ken Arromdee]

On Sun, 30 Dec 2012, John Funnell wrote:
> When a user makes their first copy, their acceptance of the
> anti-patent license is also an agreement to the restrictions on usage.
> If a US person violates this by entering into an agreement for a
> limited-scope patent license, they violate their original copyright
> license and are thus not allowed to copy, own or use the software.

But can it retroactively invalidate an existing copy?

If I write a license saying someone can only copy the software if they
are a vegetarian, and they copy the software and start eating meat later on,
they still were a vegetarian at the moment they copied the software.  You
won't be able to use the copy restriction like a use restriction because the
copy restriction only applies to conditions that are true when the copy was
made.