I guess people trust Taxis a lot more than any random unlicensed car - thus I don't think it's pointless... plus, aren't there private drivers in NY? If I have

I guess people trust Taxis a lot more than any random unlicensed car - thus I don't think it's pointless... plus, aren't there private drivers in NY? If I have a lot of money and want to hire a cousin (or even some non-relative) to drive me around, is it illegal?