Is it a good idea to put someones social security number on facebook?

[that chick]

Ok, Long story short, my best friend put her dad's old college ID card ( from 1976) on her facebook page. SHe was comparing her picture and his picture and how much they look alike. However, on his college ID it has a number that looked like a social security number, and his birthdate on the card---- for the whole world to see on facebook because she has 1,000 friends. SO- I called him- and he was upset about it and demanded she take it down, I feel awful. Because she is so mad at me... but I felt like it was the right thing to do. I didn't want to confront her myself because I knew she would just get mad and keep it up there.... and I thought it was right to tell him, so if someone steals his identity he would know... or be on the look out for it-- Did I do the right thing?