Power goes out, businesses do business with hard copy rather than point-of-sale, and report less to IRS.
In 1965 (?) the power went out in NYC, and nine months later, a baby boom. When power went out when I was a cop, we did more running back and forth as people flipped out. Accidents because traffic lights were out. Burglaries spiked. More and more people, were also in public, openly having sex. The hookers ran around naked. Orders were given to avoid arrests unless absolutely necessary so roof lights and a tap on the siren were the warning. People ran like cockroaches, and we criss-crossed back-and-forth the sector, all night long. All the ghettoites came out doors to avoid the heat, and the streets were teaming with people.