Not sure that's a good idea, czechboy.
I personally get pretty suspicious when something asks me for an email address, and for unknown software I'll definitely be entering a bogus address unless I absolutely HAVE to enter a valid one. Now, of course I know that DonationCoder software has no bad intentions, but if I was a new user that didn't know about the site yet and just wanted to try FARR or Screenshot Captor? I would enter bogus information.
Also, I think there shouldn't be too much about donating in the newsletter, as it could easily be seen as begging. Iirc we've seen one or two posts from people who couldn't remember signing up for the newsletter who thought they were being spammed, and if the newsletter was full of donation-begging... then that could easily seem worse.
On the other hand, I don't have a better solution I'm afraid. The license policy does seem strange, even if I understand mouser's reasons.