How to reproduce - Make sure the machine is Vista Ultimate and UAC enabled.

1.) Install 6u10 RC build of JRE
2.) Uninstall Jre 6u10 from the Add/Remove
3.) Check HKLM\JavaSoft\update\policy Key path
Uninstall should remove all the registry keys installed by JRE on the users machines.

1.) Install 6u10 RC build of JRE
2.) Open JCP and go to update tab. Click on "Update Now" button.
3.) Don't proceed with update. Close all the Java windows
4.) Uninstall Jre 6u10 from the Add/Remove
5.) Check HKLM\JavaSoft\update\policy Key path and HKCU\JavaSoft\update\policy Key path
Uninstall should remove all the registry keys installed and created by JRE on the users machines.