My kids’ sorority had soberers at parties. When it was your turn, you were not allowed to drink at parties and if they saw a sister was too drunk they would hand over a bottled water as a sign. They also required the fraternity they are have social with to have designated drivers to get them to and from a party. I was told one time they noticed a driver was drinking at the party, and the sorority’s social director reported it to the fraternity’s social director. They didn’t have another social with the fraternity for some time. Ranking is important when it comes to Greek life. The way ranking is often determined which fraternity or sorority you are having parties with.