Actually not quite.
When we bought our used E350, we were provided with an inspection check list to show us what they did with the car to be able to call it CPO. It is CA Law.
California's Rules For Sales of "Certified" Used Cars
Yeah, but the question is; did they actually check everything on the list? I'm going to lean towards 'unlikely'. If you return for service, they'll more than likely take care of the problem, but they're hedging their bets on the percentage of cars that won't come back.