I mean... the problem is generally people in Japan follow the rules and put the safety of others above their own desires. That just isn't the case in the US often.... as witnessed by the people literally spitting in the faces of Uber Drivers and other people trying to enforce rules they don't agree with. I think if Disney believed people would follow the guidelines/rules and do as they were asked, things like this might happen. But here it would have the danger of turning into a situation of "give them an inch they will take a mile" easier to just have stronger wider boundaries.
Also...about the mask-less photo spot idea... I mean if each person stands in a spot, removes their mask and is quickly replaced by someone else in the same spot taking off their mask... seems like you're breathing in the air of the last ten people standing mask-less in the same spot. I don't know if it's dangerous or not, but seems to be tempting fate in a country that has a much higher rate than Japan currently