Sun's implicit threat?

From Sun's press release on their "release" of 1,600 patents:

SANTA CLARA, Calif. - January 25, 2005 - Sun Microsystems, Inc. [NASDAQ: SUNW] today announced the largest single release of patent innovations into the open source community by any organization to date, marking a significant shift in the way Sun positions its intellectual property portfolio. By giving open source developers free access to Sun OpenSolaris related patents under the Common Development and Distribution License (CDDL), the company is fostering open innovation and establishing a leadership role in the framework of a patent commons that will be recognized across the globe.

"As the largest business contributor to the open source community, Sun has always been an ardent believer in open standards and the open source process going back to the inception of this company," said Scott McNealy, Chairman and CEO, Sun Microsystems, Inc. "The release of more than 1,600 patents associated with the Solaris OS far eclipses any other vendor's contribution. Today represents a huge milestone for Sun, for the community, for developers and for customers."

Sounds very generous. Except, er... as I read it they are only "releasing" the patents for use with the CDDL. Not the GPL, which is the one Linux uses.

In other words, Sun seems to be saying: "If you want to use an open-source operating system, you'd better use ours, because we reserve the right to bring lawsuits using those patents over Linux."

Anybody see cause for another interpretation?