Soldato
Because when/if you have a crash and you end up disabling someone, and if the insurer finds out you've been fronting (and on a big claim, they will investigate) either;But I could legally drive the car, ie not be pulled over for not having insurance. How would the insurers know who the actual main driver was anyway?
1) That poor sod will have to sue you for his care costs (which you will not be able to afford) and will end up with nothing, because your insurer will have disowned you
or, more likely;
2) Your insurer will still pay out for the victim and then sue you for the money (which you will not be able to afford) and it will bankrupt you, because your insurer will have disowned you
To reduce your premium, add your mother as a named driver.