Wouldn't this be trivial for a bot to bypass? If you know the email address to be used, just get the gravatar for that email address and compare it to all of th

Wouldn't this be trivial for a bot to bypass? If you know the email address to be used, just get the gravatar for that email address and compare it to all of the images in the lineup. Depending on how it's implemented (haven't looked at the code) you might even just be able to compare the URLs used to display the gravatars...