We've proactively pulled (meaning no one threatened us or asked us to do it) our QRCodeCF Library from public availability due to internal concerns about GPL.  Personally I dislike GPL due to its viral nature - it makes using any GPL code in any software that you intend to use for commercial or proprietary systems extremely risky, and we simply don't want to perpetuate that.  We write software to solve problems, and not surprisingly I feel those who write software should be able to get paid for doing so and not worry that their entire business might have to be given away because of some insane licensing issue.