I would think that the ajax API could also be twisted to their needs. It requires an API key that Google puts some limits on, limits that they might want to apply to Scroogle in any case.
http://code.google.com/apis/ajaxsearch/
http://code.google.com/apis/ajaxsearch/key.html
That may just be disinformation though. For example, if you can spread your usage over multiple IPs, you might be allowed more searches than if you told them your API key for all your requests on multiple IP addresses.