Which statement about how to stop or park on a slope is NOT correct?

1. ①Anti-rolling measures are required even when parking on a slope inside an apartment complex rather than on a road.
2. ②If the driver stays in the driver's seat and is operating the brake directly, wheel chocks are not required.
3. ③Once the parking brake is applied, no other anti-rolling measure is needed.
4. ④Instead of a wheel chock, an item such as rubber or plastic that can stop rolling may be placed against the wheel.