Depends. Are we talking knives/clubs or guns? What kind of guns? What are the circumstances?
If it's a store getting robbed and didn't seem like anyone was going to get hurt, probably not. Not my problem. But if it looked like someone innocent was going to be hurt or killed, I would. I've seen plenty of videos where the robbers kill a clerk, or customer. If someone was getting mugged on the street, I would 100%.