OS: Windows Server 2008
Java: 6u18

In 6u10 or later, 'Default Java for Browsers' checkbox for IE in Java Control Panel
is gray-out and keeps user from disabling it, if running Windows is Vista or later.
It is documented in 6u10 Update Release Note.

    http://java.sun.com/javase/6/webnotes/6u10.html

But this checkbox can be toggled by hitting space-key.
And if logon account is an 'administrator', he can actually disable Java plugin.

This is harmless since it is re-enabled, but might confuse user.
The checkbox should be removed or completely disabled.