A Rogue Hitchhiker is a member of the The Hitchhiker's Guild who has fallen off the path described in the The Hitchhiker's Oath, usually to seek power, glory or wealth for themselves. The most famous example of a Rogue is King Felix I, who declared himself a benevolent sovereign of Kingdom of Ozarka.
The The Regulators are an internal task force that corrects or neutralizes Rogue Hitchhikers. Since membership in the organization is so informal, and guided largely by induction via Shibboleth, the most effective way to address a Rogue is simply to kill them. This leaves the network intact and doesn't rely on their compliance with an Oath they broke in the first place.