It’s an example of “Tragedy of the Commons” also called “Tragedy of the Freedom of the Commons”.
Ten Real Life Examples of the Tragedy of The Commons
Basically, when it is in everyone’s individual interest to maximise their use of a common good, and the there is no reason for an individual to limit or reduce their consumption of that good, there comes a point where that good is overused and depleted to an extent it becomes of no use to anyone.
In this instance, the “good” is access to space and fresh air, far from the madding crowd and free from the risk of infection by a respiratory disease.
But if lots of people do that, the good is lost. It is crowded, there is increased risk of infection, there isn’t enough space, people are too close together, the freedom from the worry of infection is lost. There is also the additional factor of increased risk of accidents during unnecessary journeys (and infection risk in crowded situations where people might be out of their cars e.g. traffic jams, car parks, petrol stations).
This can be seen in action in pictures from Snowdonia etc recently. Somewhere that is usually empty became crowded.
People might say “Ah, but there is a spot only I know, I’ve never seen anyone there before”. But it is difficult to know accurately how remote/secluded/unknown a spot really is. Even the top of Mount Everest becomes crowded at times.
Just because you’ve never seen anyone else there, doesn’t mean no- one else knows about. There has been a recent massive increase in the number of people with time available (people laid off, off school/work etc). There has also been a massive reduction in the available activities for that time- no cinemas, concerts, gyms, sports matches, limited shopping etc. So with more people and less to do, somewhere that is usually quiet on e.g. a Wednesday afternoon could rapidly and unexpectedly become a crowded hotspot.