The first half of this program:
Multiple Account Login Detector (AE Detector) sets a special cookie that is not deleted on logout and is stored in another section of the PC then the normal cookies are. And the cool thing is this cookie does not get deleted when the user deletes all of the browser cookies, as it is outside the standard cookie folder location.
They can switch browsers all they want. makes no difference.
as for proxies, there is a mod on this site that prevents proxy site use, and allows AOL and dial up users to still gain access. There is also the 2 IP info and Proxy to IP mods that will help with that issue.
There are so many mods available for vB that will help you prevent over 99.5% of user dupe accounts it's not even funny.
Why these features are not standard along with a standard Admin selected Real First and Last name profile fields just kills me.
I have all of these security mods and more and they all work great.