OK you toy lawyers... I've been in FLOSS dev for over ten years and have plenty of experience with GPL compliance.
1) ccminer is hopelessly non-compliant. The core code is GPLv2. It links to some dependencies which are mostly LGPLv2 system libraries. A few of the algo kernels are licensed MIT, BSD or Apache. So far, so good. Now there are a couple dozen kernels with no stated license whatsoever. The sources being public does NOT make them open. They default copyright to the original author. Using them in any way, without written permission from the original author, leaves you open to legal action. ccminer linking to them breaks GPL-compliance and distributing its binaries is illegal.
2) Just because someone uses GPL'd code in some private project does not give you any legal recourse towards them. You have to legally obtain a binary release first. It is perfectly fine to use GPL code in something you never release to the public. It is perfectly legal to sell a binary release privately, so long as you give the customer some means to obtain the code for that release. The sources need not be posted publicly by the original author. They can be sent to the customer via email, on a USB stick, CD or even printed on 100,000 pages and mailed, etc. Additionally, purchasing a binary only gives your rights the the sources used to build THAT release binary. The author does not have to give you SCM history and you are not entitled to future release sources without legally obtaining said future release in binary form.
3) As a continuation to #2; Anyone who legally obtains the source code to a GPL compliant project has the right to do what they want with it within the GPL licensing framework. This includes modification and redistribution, including to the public.
So as djm34 has been saying, adding a mining fee to ccminer is a lost cause. Even if distributed privately, it only takes one person to exercise their GPL rights to obtain the code. That person doesn't need to even know anything about code to publish it. Next some will remove the mining fee and use it privately. Eventually someone will remove the fee and release fee-less versions of the code.
Taking the opposite side of this argument is untenable. You think people will morally sit back and pay that fee if they don't have to? Bet your ass they won't. I'd be the first one in line to obtain the sources and strip the fee for my own use.
The only solution is a completely new, closed source, fee-based miner with completely new kernels written in isolation from the specs. The resulting binaries would further need to be copy protected to dissuade reverse-engineering and binary patching. How many people do you think would trust that?