Was I out of line?

I forgot to blog about this a couple weeks ago, so I will now...

I took the kids to the little store around the corner from my house (ok, it's a liquor store technically, lol) for an after school treat, and I let them go in alone. I was sitting in the car and watching them through the window. The only thing I asked them to buy me was a bottle of water. When they came out, they had forgotten, so I asked my son to go back in. He hesitated, and then asked DD to do it for him. When she went in, I asked him what was up. Apparently the guy behind the counter accused DS of stealing! He asked if there was "anything else" as they were checking out, and then pointed to the cameras that were in the corner. He said he could check them if he needed to. DS just kept saying that no, that was it, and then paid and came out. I? Was furious. Beyond furious. I called DH and asked if I should/could go in and say something, and he said I could if I wanted to.

I waited for the couple customers to leave and then went in. I asked him if there was a reason he accused my son of stealing. He immediately started to apologize and said that he hadn't. I repeated what he had said and he tried to explain that he hadn't meant to accuse him...he seemed really nervous about it. I said, "look, I know you get a lot of kids in here and I'm sure some of them steal...I know you don't know my son but as a mother, it's really upsetting to have my kid come to the car shaken up about something he didn't do!". The guy kept apologizing to me. I even acknowledged that I knew my son was wearing a hooded sweatshirt and that I could see why he was suspicious, but I said I work hard at raising my kids "right" and I'd appreciate if he never did that again.

When I went back to the car, my son was beaming. I told him to never make me regret jumping to his defense by NEVER stealing anything, ever.

The thing is, I can't help but understand why the storekeeper would be suspicious. He doesn't know my son. So was I out of line? I could have just talked to my son about why the guy was acting that way and try to make a lesson out of it that way...but I don't know, I guess the maternal instinct to protect him was just too strong that day. What would you have done?