Hi Chris,
>>I was wondering how you and other users handle the GPL license
The FNET stack is LGPL.
It means, that ONLY changes/fixes in the FNET stack source code should be shared with community, what is pretty fair.
You should NOT open your proprietary code and you may use LGPL with any other license code.
(If you still need a special exception clause, it can be added).
One additional bonus: LGPL is compatible with GPL, so you can use FNET in GPL projects too (LGPL automatically converted to GPL). Many people do not know about this LGPL feature ,that is why FNET is dual licensed. So you can choose what license to choose in your project.
Best regards,
Andrey Butok