They know The Alexa rankings are crap and thats why they removed themselves so as to think themselves brilliant...LOL jk
The general public does not use Alexa or Alexa toolbars, and if they have spyware protection it will remove it when the computer scans. The only way you can get a decent read is by installing the widget on your site, this eliminates the need for your visitors to have an Alexa Toolbar. Altough if you have "gamed" the system in the past, your rank may go down, because your traffic rank is truely not as high as you are rated in most cases. If you feel that you are getting a lot of traffic and you are not getting credit install the widget and your traffic rank will go up in Alexa. Check out my article for more info about this subject, and how to improve your score. http://www.everythingkitchens.com/increase_alexa_rankings.html