Dingle - be aware that you have to consider at least two situations - License and Copyright.
As I understand it, I'm not a lawyer, Licenses are designed to move potential publishers away from simple copyright rules into a much more defined relationship. The various gaming licenses help the licensees by defining a working relationship to use some 'intellectual property'. They also help the license giver by moving any disputes away from simple copyright law and into the framework of the license. I believe the GSL has (had?) a clause that legal disputes would all be paid for by the licensee for example.
The limitations on your publishing, previously described by copyright law, are changed forever when you agree to publish under the OGL or most any other license. The license becomes the rule because you have chosen to be bound by it. It is a fools game for a licensee to spout rules of copyright unless you can somehow make the license illegal or non binding.
I do not know what freedoms you might gain if you relied only on copyright. Nobody is eager to pay the court costs to find out.
S
Thanks I reckon I'll stick to the SRD. There still lots in there I havn't done yet.