I have been aware of that and have made some changes to the site to address it. Unfortunately, they are not Americans. The change I implemented last night adds a question to the registration process that requires an additional click that most bots (which is what they are) are not aware of. I have added another feature that should help too.
If we get more, I will start monitoring, because there will be a greater chance it is a person. But man, I'm with you, I hate that crap.