The seopros at http*//www.seopros.org/services/cloaking.htm state that they will investigate whether a site is using cloaking, pagejacking, or abusing "best practices" to manipulate search engine results. They also provide a cloak busting tool to check whether a page is cloaked.
Is this dangerous? you bet. When someone becomes the sole arbiter of what is acceptable and what should be exposed, there is always the potential for either innocent misunderstanding or down right harm.
You doubt this? Ok suppose I were to set up a site exposing what I considered violations of "best practices", then, those found violating my best practices get listed as "untrusted" businesses.
Do you know what would happen? Why that very page which describes investigating abuses of "best practices" would be listed on it. It uses CSS to alter the size of header tags, and contains not one, but two hidden forms, one of which is full of keywords (search engines). Now if I had such a site, I would rationalize in my zeal to clean the world of such abuses that this was done purely to influence search engine ranking, and I would list them as "untrusted", thereby harming their credability.
But you know what? They probably just forgot that code was there, or they decided to comment out the forms in case they need them later, but if they rank ahead of me then I want that stuff out of there.