@michel v: Agreed, but thats the same with everything. For example, look how many Linux Distro's are out there. Gentoo, Debian, RedHat, SuSE, just to name a few. If something doesn't work in one, they'll move onto the next.
As TechGnome pointed out, if some is determined to get in they will. There is no ulitmate solution to this problem, and there probably never will be.
The code I have submitted is just an idea to make things just that little bit harder for a spammer to do his/her job, and I have not touted it to be the ultimate solution to the problem either.
I'm just trying to help people who are getting these problems. I've been a victim of this spam myself, and have put in preventative measures to stop it, so far it's been quite successful, however if the spammer was determined enough to spam my site, they will, there is very little I can do about it.