Can you elaborate a bit more? I don't know how I can refute his concern (of course I'm not in the field though).
It seems true that if Prop 22 were passed, he would have to become an employee for one company, so he wouldn't be able to work for 5+ companies at the same time.
It seems true that if Prop 22 were passed, he would have to become an employee for one company, so he wouldn't be able to work for 5+ companies at the same time.