What's the policy on UG users copy/pasting stuff from other sites?

I have reasonable cause to believe some users are doing so, and they are thus ascending the rankings unfairly. I just rejected two tabs from the same user (with almost 200 tabs) for doing so, and this also happened about two weeks ago with a different user (~20 tabs).

Basically we don't have problem accepting stuff that is free to share.
Quote by zappp
emad I'm gonna ban you, seriously.