Yes. The recruiter tracking code ("?recruiter_id=X") at the end of the URL triggers a cookie that is stored in the user's browser. The browser will send the cookie's information to NationBuilder once a user takes an action within your Nation (signing up via a petition, RSVPing for an event, participating in a survey) and assign the recruiter to the user's record.

A recruiter cannot be logged in a user's profile via a recruiter tracking code if the user does not enable cookies in their browser.