RHEL is mentioned in this attack on Google's use of the Linux kernel in back-end servers.

http://www.theregister.co.uk/2011/04/21/texas_jury_says_google_infringed_linux_patent/

At least some of those sued were using Red Hat Enterprise Linux (RHEL) on the back-end. Google apparently uses its own version of Linux across its famously distributed infrastructure.

Bedrock has also asked for an injunction preventing Google from infringing on its patent, but the court has yet to rule on this. Red Hat has also intervened in the case, asking the Bedrock patent be ruled invalid.

http://fosspatents.blogspot.com/2011/04/texas-jury-finds-against-google-in.html