Will transmission rates be higher than if everyone stayed at home? Of course. But that isn’t the alternative. I do not see any realistic option of 18-22 year olds sheltering at home through 2020. They will be out socializing, and meeting friends, and probably trying to work and/or travel, even domestically. Adults expect to resume their lives, even to travel for pleasure, judging by many posts here. It seems cruel to deny young adults that option.