Dual-Licensing Situation

[AR]

Federico Di Gregorio wrote:
> Il giorno gio, 05/06/2008 alle 16.08 -0400, AR ha scritto:
>   
>> Arnoud Engelfriet wrote:
>>     
>>> AR wrote:
>>>   
>>>       
>>>> I'm looking at a situation where someone has released some code under 
>>>> both GPLv2 and a proprietary license.  I'm being told this:  If you 
>>>> develop (and do not distribute) code using our GPL code, you cannot then 
>>>> get a proprietary license for your code.  That is, if I merely *use* 
>>>> their GPL code, I forfeit the right to buy a proprietary license.  Isn't 
>>>> that a further restriction placed upon my code by them, and therefore a 
>>>> violation of the GPL?
>>>>     
>>>>         
>>> I don't see how. You don't lose any rights granted to you by
>>> the GPL.
>>>       
>> Thanks for your reply.  Yes I do lose rights, so let me try a different 
>> viewpoint:
>>     
>
> IHMO you don't lose any rights. This is like saying "I sell motorcycles
> and I'll sell them to anybody except people that already own a car". I
> am just stating how I'll behave as a vendor but I don't reduce in any
> way your right to own a car. Yes, they are trying some mental trick on
> you to force you to get a proprietary license right now, but they are
> not limiting your rights in any way

I don't think your analogy is an accurate representation of the situation.

Scenario 1:
I am the copyright holder of my code.
I developed it using the $1000 proprietary license of dual-licensed code.
I release it under the GPL.
A company approaches me that wants me to dual-license it for
$5000 to include in their non-free code.
My code is worth $4000, and I can live off that for a while to improve 
and GPL-release my code.

Scenario 2:
I am the copyright holder of my code.
I developed it using the GPL license of the dual-licensed code.
I release it under the GPL.
A company approaches me that wants me to dual-license it for
$5000 to include in their non-free code.
My code is worth $5000, but I can no longer get the $1000 license AS A
SOLE RESULT OF ACCEPTING THE GPL.
I have lost my right to dual-license my code AS A
SOLE RESULT OF ACCEPTING THE GPL that I would have had otherwise.
I no longer improve and GPL-release my code because I can't afford it.

My contention: the two licenses are inextricable, and therefore materially
constitute one license:  The GPL + other restrictions.  That is a 
violation of the GPL.

What terms did they materially add to the GPL?
"By accepting this GPL license, you waive the ability to acquire the 
propietary license."
The result?
The acceptance of this so-called GPL license does something that 
accepting the GPL alone would not do.

That might be the best summary of the problem I've come up with yet.