Once you have presented a page, with a form etc., to the user you have lost control over it. The user can muck around with it: enable radio buttons - do whatever they want (if they know how).
The important thing is that you ignore or discard any return (posted) values that you are not expecting, and check that the values you are expecting are acceptable.
disabled="disabled" is how we disable radio buttons - or you can hide them or don't include them.
"I'm here to save your life. But if I'm going to do that, I'll need total uninanonynymity
." Me Myself & Irene
Validate your HTML