Cell phone etiquette in PUBLIC

I guess somewhat similar to PDA (public display of affection), I do believe there is a LIMIT! While having a business lunch a woman having a convo for the entire restaurant, I really felt a part of the convo whether I wanted to be or not. So loud was she that I felt obliged to join her, so against the advice of my companion I approached her and said, "You are right, people who do that in public should be punished," and left. In the parking lot she said, "Let me apologize, I don't usually speak that loud in public", I smiled and asked, "well what was the special ocassion?" She said, "" I just get excited at times and I forget where I am." And she just left. Text people, especially if you are not a quiet talker when you're on the phone.