1) Diamond Princess quickly locked people in their roomsWell let’s use some facts here. The diamond princess cruise ship would serve as a good example. Of the 3711 passengers and crew, there were 712 infections. Now that is about a 19% infection rate and I feel we can agree that having everyone quarantined on a cruise ship would provide some pretty close contact and easy transmission. So if we take your number of 100,000 people at a 19% rate we are looking at around 19,000 people getting infected. Mind you this is before the CDC changed course on wearing masks. There have been studies that show there being an 80% reduction in infections when masks are worn. So 80% of 19,000 would be about 3800 cases. This doesn’t factor in the amount of people that already have antibodies that would produce a herd immunity effect. I can only imagine the herd immunity and people with antibodies to be much higher come August. So yes, anything at this point is just kicking the can. If you are scared, stay home.
2) You think football fans are going to wear masks?? I gotta laugh, sorry. That's comical.
3) Yelling has a higher virus transmission rate (air coming from deeper in the lungs).
4) Yes, a (small) part of the attendees will probably be immune already