What's arxiv “endorsement” policy?
I believe the help page describes the current endorsement policy.  You may also have fallen into the category described by "We may give some people automatic endorsements based on topic, previous submissions, and academic affiliation."

As I understand it, most people are in that category and never see the endorsement system in action.  In practice, it seems to get applied to cranks and to people who look like they might possibly be cranks (e.g., people with no academic affiliation, or who are writing on controversial topics).