"CentOS and others--Lineox, White Box Linux, Tao Linux, X/OS Linux and Scientific Linux--all rebuild a copy of Red Hat Enterprise Linux from the source code components Red Hat releases."
http://news.com.com/Programmers+bypass+Red+Hat+Linux+fees/2100-7344_3-5632434.html
Here's a guy at eWeek advocating ending your paid Red Hat subscription and just getting the your security updates from somebody else for free. If that's not proving duplicity between Red Hat and these clones I don't know what would.
http://blog.eweek.com/blogs/eweek_labs/archive/2006/03/02/8192.aspx
Well, duh. But RH doesn't release all its code, genius.