I accept them just fine if it's by someone who rejects copyright of his own works. I don't accept if it's done by hypocrites.

> Do you just accept GPL violations?

It's hard to violate the GPL without plagiarizing.

I thought plagiarism was an issue of false attribution? If my product gives attribution to the original authors, but I do not release my source code, then I am in violation of the GPL, but I am not a plagiarist.

> I thought plagiarism was an issue of false attribution?

Yes, that's precisely what I've seen people get annoyed about when the issue of copyright violation comes up.

> If my product gives attribution to the original authors, but I do not release my source code, then I am in violation of the GPL, but I am not a plagiarist.

I thought the GPL allowed binary-only distribution as long as there was a link or similar in the program to somewhere the source was available, but apparently not.

http://www.gnu.org/licenses/gpl-faq.html#UnchangedJustBinary

"The general rule is, if you distribute binaries, you must distribute the complete corresponding source code too. The exception for the case where you received a written offer for source code is quite limited."