Just an observation, though I don't really think it's the theater's fault:
Theater with the most likely patronage of people who will come no matter how sick they are. I'm not exactly certain why, but having the unique experience of having to see the same movie on the same day at three different area theaters due to friend commitments, this theater stood out as the one that attracted such selfish and hygiene-challenged clientele. The other two theaters were also the other area "nice ones" so it's not that.
I guess the theater could turn these people away and make them go home. Just a warning, though...be careful and aware of the threats to your immunity here.