Because the virus is in stool, if you happen to be downwind from toilet vent stack you could get exposesd. That's how it spread on cruise ships when everyone stayed in their cabins.
The Chinese published a paper where people locked in their apartments in Wuhan still got sick, and they identified the plumbing.
There was a study from NY stating "66% of people who stayed inside caught vid19".
Because the virus is in stool, if you happen to be downwind from toilet vent stack you could get exposesd. That's how it spread on cruise ships when everyone stayed in their cabins.
The Chinese published a paper where people locked in their apartments in Wuhan still got sick, and they identified the plumbing.