I think one of the reasons why this system exists is to keep airlines from buying slots they will not use, which could both be anti-competitive and bad for the

I think one of the reasons why this system exists is to keep airlines from buying slots they will not use, which could both be anti-competitive and bad for the airport (passengers = money, planes = service, support, fuel, etc). That's all fine in normal times but in a pandemic crisis (or environmental crisis) it's very silly.