@mathmom, the studies that show drinking at home isn’t protective against binge drinking included households where parents bought and served alcohol to their children and their children’s peers. When families that served only their children (and not their peers) and were also drinking with them as part of a meal were considered separately, the rate of binge drinking dropped.
All we really know for sure is that 1) outright forbidding alcohol and 2) being overly permissive about alcohol by providing the keg, etc., do not work. It’s unclear what does work.
We chose to err on the side of allowing it for our children (not when their friends were over until very recently) during their late teen years. I don’t know whether this is permanent insurance against binge drinking, but so far, so good.