Wheel chocks are mandatory for trailers and caravans.
What about a 4x4?
Wheel chocks are inexpensive items and easy to pack. When jacking a vehicle with hi - lift or 4x4 jacks, they become unstable due to the long suspension travel on 4x4’s.
Place a wheel chock at the front and rear of the wheel diagonally opposite the corner being jacked up to prevent any roll, also be aware of sideways sway. Engage lowest gear and hand brake. When rear is being jacked up, the hand brake becomes compromised.
Remember safety first!