Clash of the parenting styles

You love your friend.  You have so much in common: music, hobbies, religion, political leanings, clothing styles, careers before popping out kids.  But when it comes to parenting, even our closest friends can surprise us with their discipline choices.  Our friend  Sam is still recovering from behavior she observed while dining with her high school friend Jamie. 

Jamie’s 18 month old son was clearly over-tired and kept hitting her.  Her husband jumped up, got really angry and said, “Do you want a spanking?”  Sam’s immediate reaction was “Say no, Say no.”  The little boy burst into tears and the father proceeded to spank him in front of us.  It was really uncomfortable to watch and I haven’t made plans to see them as a family since.  “In theory, I’m okay with different discipline styles.  In practice, I don’t want my kids to watch another child getting spanked.  I think it scared them. They kept asking why his daddy hit him.”   Have you ever had a similar situation?  How did you handle it?