MyBBz.net 's Plugins List

[ZiNgA BuRgA]

When I say "useless", I mostly mean to someone who's actually targeted your site.
In a way, if you make your site slightly different to the millions of other forums out there, this difference may be able to fool a bot which is trying to scour these forums to exploit.  It would only take a bot coder like 30 seconds to write a work around to either method, but if not many forums have it, they probably won't bother.

So in a way, it might prevent bot-based registration, but it's not something I would rely on, since it's only a matter of whether the coder can be bothered to add the exception in (if it's popular, it will be added in).
And also, whilst most bots may not parse Javascript, I'm sure the good ones can attach onto a fully fledged browser and WILL parse Javascript, effectively defeating this plugin.