There is an advantage if the DNS is lying to you. In France for instance, the
executive power is now allowed to unilaterally (who needs judges?) impose to
the major ISP the censorship of sites that are supposed to turn innocent
citizens into terrorists (and the list of censored sites is secret). This
censorship happens at the DNS level: those DNS pretends there is no site
bearing the name you type (typically in a Web browser). That also means the
censorship is pretty ineffective: you only need to specify foreign DNS
servers to bypass it.
Other attacks to Net neutrality happen through DNS servers for commercial
reasons. Again in France, an ISP used to block the content coming from
Google's ad servers. Whenever a user was requesting a page with Google
commercials, it was altered independently of the wish of this user.
Another common practice is to return a page with commercials instead of a 404
error.
