The ninth Rule of Acquisition states, "Opportunity plus instinct equals profit." Sydney Charlet has the instinct and found the opportunity for great profit.
Jalopnik explains that legal parking in New York City is very expensive, sometimes runnning into six figures for reserved spots. Illegal parking can get pricey, too, due to tickets issued when street sweepers arrive. So some residents pay Charlet to sit in their cars. When the cars are about to get ticketed, Charlet moves them to avoid the fines.
This wasn't Charlet's planned career. She started her business after getting laid off from a marketing position. Clearly employers in that industry don't appreciate her cunning.