I have no relation with the announcement and know nothing more than you do, but
it doesn't sound too out-of-this-world to me: go read OS-research papers
and you'll see that there used to be developpment on commercial unixes (like
SunOS and Ultrix) contributed from universities (through NDA agreements) but
it has given way to free Unixes now (it's much easier for the researcher to get
it, no need to sign any NDA, no need to pay anything, etc..).
The key point in the announcement, is that whatever changes you do will go back
to Sun who can then use them: in clear, they make it easier for universities to
enhance their OS, so that they get top-of-the-line researchers working on their
OS for no-money.
Makes total sense to me.
Stefan