Google doesn't want people having a bad experience on Google which would drive them to consider any other source for search. If a search turns up an article and preview and a click-through doesn't show the same content, Google users will be annoyed, which will drive Google to act.
Google's anti-cloaking policy, while presented as a benefit for users [which it is], is strongly in Google's best interest to enforce as well.
Google doesn't want people having a bad experience on Google which would drive them to consider any other source for search. If a search turns up an article and preview and a click-through doesn't show the same content, Google users will be annoyed, which will drive Google to act.
Google's anti-cloaking policy, while presented as a benefit for users [which it is], is strongly in Google's best interest to enforce as well.