MGM has announced that they will be bringing back charging for self-parking. The fees will be reintroduced in phases, starting with events this month, then expanding to all casinos by June 1. Valet parking will start up again on May 25. Valet and event parking will be cashless.
According to MGM, the first hour of self-parking is free for everyone; three hours of self-parking will be free for locals; self-parking will also be free for active and veteran military, Pearl or higher status for M life members, and holders of the M life Mastercard.

Caesars reinstituted paid parking last October, though locals, hotel guests, and Caesars Rewards Platinum and above members park for free.