I would probably do something like this:
- Say something to DS like, "Honey, this is a public space and anyone can sit in an empty seat."
- Then turn to the woman and say, "I'm sorry, that wasn't very polite."
- Then back to DS and say, "People like to be asked or told politely about things, not shouted at." I've been workig on this with DS a little lately, he seems to be getting into a "bossy" stage right now.
Then, later in the car or something, maybe get into a little more detail....like, "I know you may have wanted to sit in that seat again, but I'm sure that lady didn't appreciate you shouting at her like that. There are gentle ways to ask someone to do soemthing, and people respond better when they're not yelled at. You could say, Please don't sit there, or, Excuse me, I was just going to sit there, or something like that." It's always helpful to give them something TO say or do, since often they don't know what to say or do and that's why the 'rudeness' or bluntness comes out.
I actually JUST had a conversation with DS this morning, as he shouted "don't touch it!" when I went to play with him with one of his toys. I said, "If you'd like me to not touch something, you can say please don't touch, mommy. I don't like beign shouted at." Know what? He looked at me for a couple seconds, and said, "no touch mommy peez", and I said, "OK, thank you for being gentle" and got a different toy.
AND, ITA with the PP who mentioned modeling. Modeling is the single most influential way to help your children navigate through social situations, as far as I'm concerned. So, model your response to his rudeness as the way you'd like him to be with other people - don't reflect his rudeness back to him, or he'll just continue to do it.
Also want to agree with the PP that spanking him for being rude is not the way to handle it - basically, that's teaching him that when someone does something you don't approve of (i.e., you didn't approve of his rudeness), you should hit them...what's to stop him from hitting someone the next time they're doign something he doesn't like, instead of just shouting at them?
You can be firm, model, give guidance, and still be gentle and polite...it's entirely possible.