Once a pool of money has been allocated to a city or region, the people who are paid to quarantine would be determined by auction. There are many options around how to design pricing mechanisms to incentivize consecutive days of quarantine and other types of health improving behaviors. Based on the committed payments for a city, the price of remaining quarantined would be set on a daily basis.
Consider what the cost might be to pay to place 10% of a city’s population into quarantine. I believe that it costs significantly less than minimum wage for those people. The population that would be quarantining would be the young, elderly, the sick, and those for whom working at home is possible. Quarantining a sizable portion of a population dramatically slows the progression of a virus. Even at 30% of the population, I expect the price would remain well below minimum wage. This would have a dramatic impact on the pace of spreading.
That is from Nate Baker, enforcement would be by cyber-surveillance.