must send modifications license acceptable?

[Patrice Dumas]

On Sat, Aug 25, 2007 at 11:16:34PM +0530, Rahul Sundaram wrote:
>
> A requirement to send modifications to anybody is non-free. A request to do 
> so as in the Academic Free License is not.

A request? It is not a request, it is an obligation, there is a 'must':

  You must make a reasonable effort under the circumstances to obtain the 
  express assent of recipients.

The 'under the circumstances' relax it a bit, but doesn't seems to make
it not an obligation, only that if the other copyright holders cannot be
joined by the mean of the coordinate that are visible in the package
documentation, then the express assent isn't required. But this really
looks like an obligation.

I am not an english native speaker, though, so I may be completly wrong.

--
Pat