Want to get involved in developing SMF, then why not lend a hand on our github!
This has actually been tried in the past and doesn't work nearly as well as you might think. The bots authors are smarter than you give them credit for, and if you build it into the core, it is worth their time to reverse engineer.
Oh, it absolutely would be worth their time to investigate... say by looking for a link on the page whose text is 'register'...