"Running unsigned applications like this will be blocked in a future release..."
or, for self-signed applets
"Running applications by UNKNOWN publishers will be blocked in a future release..."
I think I see the point — this will give the powers that be the capability to shut off any malware java applet that is discovered by revoking its certificate.
The unfortunate cost of this is that any casual use of java is going to be killed. It currently costs a minimum of $100/year and a lot of hoop-jumping to maintain a trusted certificate."