When can a civilian use physical force on someone? Are there any other times besides in self defence? Is it legal to use physical force in the event of an emergency, for example if you shove someone out of the way of a car and they end up falling and breaking their ankle, can you get sued?
What if you see someone running out a store and people running after them, so you grab them, but it turns out they weren't actually robbing anything?
Interesting story: I was on a bus and an altercation occurred between the bus driver and someone who got on with an expired ticket or something like that. It started by arguing, but then the bus driver shoved the passenger off the bus. Then the passenger punched the bus driver hard in the face. Then it was a full fight. The police arrived and put the passenger in handcuffs, and it seemed like witnesses took different sides as to who started it.
Was it legal for the bus driver to shove the passenger off the bus for not paying? Was it self defense that the passenger hit the driver back? I know some bus companies have policies telling the drivers not to get physical, just call the police if there's a problem.