Britney went to dinner with friends. Britney was a little late but her friends were way early. They all met at a bar in the place and drank as many drinks as they could and then when Britney got there they never touched a drop and didn't let Britney see them touch a drop of anything stronger than sweet ice tea.
After dinner and when Britney left the group went back to the bar and went back to drinking. When I know I'm going out with someone who has drinking issues they need to address but haven't or are in recovery I have been known to get to a place early and have a few cocktails and then not touch a drop once they arrive. I find it easier. You might ask why the cocktails are even needed and it has been my experience that people who have drinking problems but aren't ready to address them might be a more difficult table companion than is normal and that a drink beforehand gets you prepared for the inevitable meltdown when they have their first several drinks.