@Bob_Wachter The odds of any ONE waiter or line-mate may be "negligible", but what matters is accumulated risk. If you encounter 5-10 such people per day and each is contagious for 10 days, then 10-20/100k turns about 1% risk of such an encounter PER DAY or about 30% per month.
@Bob\u Wachter任何一个服务员或线人的几率可能“微不足道”，但重要的是累积风险。如果你每天遇到5-10个这样的人，并且每个人都有10天的传染性，那么10-20/10万人每天遇到这种人的风险约为1%，或者每月约为30%。