With political support from Sens. Bernie Sanders and Elizabeth Warren, New York City Mayor Bill de Blasio, Rep. Rashida Tlaib, and several Virginia state lawmakers, airline food preparation workers took their nationwide struggle against their bosses public with a July 23 protest that drew almost 1,000 people and virtually filled the old main hall at Washington National Airport.

When you order food through an app and tip the worker who delivers it, you’d be forgiven for thinking that the money you give goes directly to that person. But in reality, some delivery apps use your tip to make up the worker’s base pay — essentially stealing the money you’re trying to give someone to maximize their profits.