For £30 is it really worth risking the car and not getting pay out ? Also points or a ban ?

Can't understand why no one would insure the car correctly how would you feel tomorrow when someone makes a mistake in a car they have just picked up and doing something to save £30 and ruins your car then you are left with nothing.
Short term surly is only way why would any seller allow you to use there policy when they have no idea who you are or kind of driver?
Also when buying a car as we all know it's a lucky bag anything could be bodged to get it away from the old owners hands. What if something goes wrong and you end up at road side with poor injured children in a crash which you can not afford to treat them to proper care .
Madness get it sorted correctly.