I am often asked and scrutinized on my Creative Common (CC) models that I release and license incompatibility with source materials that I use.  The following is intended to detail my work and answer questions.

An approved texture source meets the following criteria:

1.)  Textures license is compatible with producing a Creative Common (CC) model.  This does not mean that the source itself is Creative Common (CC) licensed, it only means that it can be used in a meaningful process to produce Creative Common (CC) licensed content.  It also means that these textures sources will not be directly redistributed (in its original form) in any package that has been produced.  Rather if the texture was to be used without any modification, a link to the provider at the source would be provided.

2.)  Explicit permission has been obtained from the site to be used in Creative Common (CC) models.  This does not mean that permission for each individual model has been obtained.  It means that I have stated my intentions to produce Creative Common (CC) content and gained approval.  It means the site has satisfied my questions as I have answered any questions the site may have regarding how I may use their source.

Approved list of textures sites:
http://www.plaintextures.com
http://www.goodtextures.com

I still doubt that your model complies with Creative Common (CC) license, how should I report you?
The following is the order in which concerns and issues can be resolved:
1.)  I ask first you please contact me and allow me an opportunity and adequate time to answer questions or correct a problem.
2.)  If you have contacted me and are dissatisfied with my resolve, please elevate the question by posting to the model.  This will invite others to the conversation and help to drive to a resolve.
3.)  If you have tried all of the above and concerns and issues still have not been resolved, please report the model to the site on which it is posted.  I will then work with the site on a resolution.

Why are you writing all of this?
I appreciate being audited and having issues identified so that I can fix them.  Additionally, I do not want my posted models littered with doubtful comments unless it is warranted.  This is written to help answer common concerns and guide a corrective process for when it is needed.

How do I contact you?
Feel free to use the form here: http://quandtum.weebly.com/contact-me.html

Recently I have been following along with a very interesting conversation happening on OpenGameArt.org, specifically http://opengameart.org/forumtopic/practicality-of-cc-by-sa.  Traditionally I had been releasing my models under the CC-BY-SA, not giving much consideration to it as compared to the others.

My notion for using the CC-BY-SA was simple, like anyone else, I simply wanted other people to be able to use my work, but also wanted credit for that work.  After following along for a bit with the forum thread posted above, I came to a simple conclusion.  I asked myself what was more important, getting credit for my work, or having my work used.  It turned out to be the latter, turning me to use a CC-0 license.  I think responsible people still tend to give credit, even if they are not obligated to.  Conversely, irresponsible people will not give credit when they are suppose to.

Bottom line, I want people to be able to use my models for what ever project they might have and not be concerned with restrictions.  I will gamble on getting or not getting credit.