What I'm getting at is that we've seen multiple reports of people removing masks while on rides. For the majority of rides, this isn't as big of an issue because the attractions are in their own buildings separate from the rest of the guests not on the ride. With PM, in travels between buildings, with people walking underneath them, through the gift shop, etc. And while, yes, CM could stop the ride and announce over the speaker that people need to put their masks back on, in terms of efficiency that just isn't viable. The ride would be stopped way too often to even bother opening the ride. I don't think guests would go so far as to "spit" on people below, but given how distance tests about breathing/speaking/coughing/sneezing travel, to have that above people if it happens sounds like a problem Disney doesn't want.