It isn’t without its complications. On my drive with Mr. and Mrs. Cabezas, they used the app to find two Lime scooters at an apartment building, only to discover them locked behind a gate. Another scooter was being loaded into a pickup truck just as the couple drove up.

There are also hoarders, who drive around picking up scooters knowing that they will eventually need recharging, even if the scooter company hasn’t yet posted them to the app. And then there are the scooters that have a flat tire or are somehow broken and require a special trip to a fix-it location.

The job requires more than just figuring out the app. Making it profitable means understanding the city well enough to know if a tantalizing cluster of scooters is in a dangerous area. Also knowing where to park, because there’s no easier way to wipe out a night’s earnings than getting a costly ticket.

There’s also the upfront equipment cost. New juicers pay Lime $10 per charger. Mr. and Mrs. Cabezas said they had spent about $250 for the two dozen chargers they used, many bought secondhand.

Still, Mr. and Mrs. Cabezas said it was worth their time. Working three or four nights a week, the couple have made about $5,000 since May, with little spent out of pocket. They said that their electricity bill had risen about $10 a month and that they spent about $5 in gas each night.

As much these gigs may be a boon to the workers, there are questions about the mobility programs’ environmental and economic sustainability. A recent study from North Carolina State University found that driving around to pick up, recharge and release the scooters accounted for 40 percent of a scooter’s total greenhouse gas emissions.