Black hats have always been making waves with all their cloaking and other ways to trick webspiders, but can Google really detect such maneuvers by black hats. As Matt Cutts notes the claims about a Danish company. "I've been following a case in Denmark where a cloaking company has been making a couple interesting claims. First, they claim that if a "brand-name" company cloaks, Google won't remove the brand-name domain. That's simply not true; if we believe that a company is abusing Google's index by cloaking, we certainly do reserve the right to remove that company's domains from our index. Next, the cloaking company claims that their method of cloaking is undetectable."
But it might not all be undetectable as: "if someone is trying to manipulate Google by deceptive cloaking, it means that a webserver is returning different content to Googlebot than to users. That's a condition that can be checked for by algorithms or manually, and such cloaking is certainly not 'undetectable.'"
So it might not be all that easy to trick the webspiders after all.