Public and private distinctions do not make a difference. Risk is the key factor to understanding why common spaces are closed and likely to remain so, at least in the way we were used to. In what is called the asymmetric loss function, a decision maker's cost of a mistake in one direction is many times greater than the cost of error in the other direction. 

Individuals with asymmetric loss functions are extremely risk averse when it comes to potential losses. Individuals often employ asymmetric loss functions in everyday life. For most people being 30 minutes early for a flight, for example, is much less costly than being 30 minutes late. 

But, because people are different, individuals decide for themselves how late they can arrive and risk missing a flight. Things get trickier when decisions regarding risk tolerance are made for common spaces and groups, because one size doesn't always fit all.

Weighing downside risks too heavily can be socially costly, because some valuable private activities are prohibited.