It's not quite that cut and dried though. In a situation like this, governments will generally defer to a body like the SAE. Without getting too far into it, to my knowledge it really hasn't been tested in court one way or the other. I wouldn't want to be the one in that hypothetical wreck, paying the lawyer to save my ass.
You can find websites that confidently say what Joe just stated and other sites that state equally confidently that they are absolutely illegal.
I have heard (anecdotally) of people getting "fix it tickets" for beadlocks, but cops can write tickets for all sorts of bs. That doesn't mean it's the actual law. A friend once got a ticket from a cop insisting that his body lift was illegal.

He went to court and the judge dropped it instantly.