This whole "who prevents cargo from being stolen" argument is moot in my opinion. If a someone wants to steal cargo, they can threaten driver with a gun. Maybe he will be able to draw a gun soon enough, maybe not. If cargo is expensive enough, he may even be killed. Also only in US drivers can have a gun. In europe there is also many trucks. What happens when driver hears something strange at night? He just pretend he's still asleep so that thieves don't threaten him. Cargo is insured and his employer will prefer to have alive driver.