I don't know all the legal issues, but intuitively it seems strange to require one employer of a contractor to be required to ensure they have insurance for non

I don't know all the legal issues, but intuitively it seems strange to require one employer of a contractor to be required to ensure they have insurance for non-contracted work. If a doctor delivers a baby at a hospital, would that hospital be liable if the doctor delivers a baby in an emergency in someone's house? If you contract someone to come in for 8 hours a month to help with payroll, are you liable if they steal money from another company during their downtime? This seems like part of an anti-Uber wave. (I have no stake in this horserace)