VW Polo as a timber transporter: Police stop small car with dangerous loading. In the worst case, not only the driver but possibly other road users would have been seriously injured.
Incorrectly securing loads in the vehicle is extremely dangerous. Always sort heavy objects as low as possible. Good transport should never slip or even fly through the car when braking - that's why cargo should be transported in the footwell or protected from "flying off" when braking using the back seat, back seat back or luggage net.