Let's face it: the overwhelming majority of users doesn't even know what JavaScript is, so including this problem between a feasible wish-list of accessibility problems is actually a relic of a bigon age when the web was a static sequence of monolitic sites with animated GIFs and the like. Let's face it: JavaScript may be supported or not supported, and that's the real problem when dealing with accessibility and scripting, so if you intend to build an accessible web site, you should provide a fallback mechanism in the case that JavaScript is not supported or ill-supported (which is even worse).
Sure, some paranoid sysadmins may configure their clients with JavaScript turned off, but they're perfectly aware that almost 100% of web sites uses this client-side language, so this means that their users will experience problems during web surfing, not to say that most of web site features won't be available. Is this a practical way to deal with security problems? Honestly, I don't think so. Forget this myth and try to focus on real scripting-related problems.
I do know that some large institutions selectively block incoming JavaScript. Scripting is still enabled in the browser, though.
I guess the workers are not supposed to surf the Web...