one person with a child versus a group of people that are trying to intimidate you and have blocked you in with another vehicle. a reasonable person would have good cause to fear for their safety and that of their child, the criteria for self defense would have been met. Of course you wouldn't just pull out a gun and start shooting, in reality as soon as you pulled it out the salesman would have gotten out of dodge, and if by chance they decide to go mental and make a threatening advance on you, you have good reason to fear for your life should you choose not to defend yourself.