planning on a starting a rental.

Recently I've been getting a lot of videos about car rentals in my feed, in both instagram and youtube. My doubt is that I know you need to have a black board with yellow letters vehicle to rent out, but people are renting out the normal white board with black letter vehicles.

What will the owners do if the vehicle gets into an accident by the renter, who will be at risk? A friend told me to tell the police if they stop that the vehicle belongs to their relatives etc.

I can't find much answers on Google and youtube. Pls explain this stuff.

ty🫂