A guy I was sponsoring was very serious about sobriety. He had been sober three months. He came home one friday to a small party going on at his house. This was an absolutely normal situation. As he walked in the door, a family member he hadn't seen for a while handed him a beer. This was also perfectly normal. It was on the way to his lips, when his sister knocked it out of his hand. He was somewhat shocked to realise how close he had come without a single thought of his own to save him. It was lucky his sister knew about his problem and what he was trying to do. She could well have saved his life.
" At a proper time and place explain to all your friends why alcohol disagrees with you. If you do this thoroughly, few people will ask you to drink. While you were drinking, you were withdrawing from life little by little. Now you are getting back into the social life of this world. Don't start to withdraw again just because your friends drink liquor."
This is the AA suggestion. Of course, in my case, there was a time where I just wanted to keep my options open, just in case I found a way to drink safely. I didn't want to tell anyone in those circumstances as it would only make it more uncomfortable to resume drinking. But if I want to stop for good, it was good advice to enlist all the help I could.