https://arstechnica.com/tech-policy/2017/11/comcast-quietly-drops-promise-not-to-charge-tolls-for-internet-fast-lanes/

For years, Comcast has been promising that it won't violate the principles of net neutrality, regardless of whether the government imposes any net neutrality rules. That meant that Comcast wouldn't block or throttle lawful Internet traffic and that it wouldn't create fast lanes in order to collect tolls from Web companies that want priority access over the Comcast network.

This was one of the ways in which Comcast argued that the Federal Communications Commission should not reclassify broadband providers as common carriers, a designation that forces ISPs to treat customers fairly in other ways. The Title II common carrier classification that makes net neutrality rules enforceable isn't necessary because ISPs won't violate net neutrality principles anyway, Comcast and other ISPs have claimed.