I get that, and the comment I was replying to was specifically refuting the "ballistic droplets" theory in favor of a "confounding variable" of them just happening to be in the same social circles.

A lot of coughing and high risk individuals at the symphony though, unfortunately.

High risk for mortality, yes. But are they higher risk for actually catching the bug when exposed? I don't think anyone knows that.

I'm not even sure how you could come up with numbers on how much viral exposure is needed to infect someone, short of controlled experiments with volunteers. The odds of killing a few volunteers seems pretty damn high, especially if you are testing with more vulnerable folks to establish a differential estimate. That's not a study I'd want to be involved in on either side of the clipboard.