It is an offence to use a motor vehicle, or allow others to use it without insurance that satisfies the requirements of the Act. This requirement applies while any part of a vehicle (even if a greater part of it is on private land) is on the public highway. No such legislation applies on private land. However, private land to which the public have a reasonable right of access (for example, a supermarket car park during opening hours) is considered to be included within the requirements of the Act.
Auto insurance is financial protection, and not just for the investment you made when you bought your car. After a really serious accident, bills for damage and injuries can easily reach into hundreds of thousands of dollars. If you happen to cause such a wreck, the victims could sue you. In the worst case scenario, assets such as your savings and home could be seized.