This works only and only if you have a TRACKER. it will also work even if it doesnt have an insurance. if it doesnt have a tracker, it would only work 2 times.
it only works if you get a car straight out of your garage and then sell it.
sometimes the loading screen takes time to load and that gives your car time to disappear. be sure to load your start menu so it would be fast.
you dont even need to buy a bike or car, just steal one, put it on your garage. then bam