New York CNN Business  — 

On-demand workers in the US are rising up against the companies they work for – using the platforms themselves to do it.

On Saturday, thousands of Postmates workers plan to manipulate the on-demand delivery app for better pay by refusing jobs that aren’t in “blitz mode,” a feature that allows Postmates to increase pricing when demand for deliveries exceeds supply.

It’s the latest example of on-demand workers leveraging the tools they have, developed by the companies they contract for, to fight back against low wages.

The coordinated protest, dubbed “Blitz Up,” is being organized by Seattle-based workers’ rights organization Working Washington. The organization has had recent success in forcing the hand of on-demand companies by organizing workers, gaining media attention and generating customer awareness of issues facing independent contractors, who are the backbone of the services. Instacart was the subject of a recent Working Washington petition and push for customers to tip just 22 cents in the app to show solidarity with workers. In response, the company reversed its controversial tipping practice in February after becoming the subject of scrutiny by its workers and the organization.

Blitz Up is an offshoot of Working Washington’s broader push for a minimum pay floor of least $15 per hour in addition to expenses and tips. They also want transparency around pay from on-demand companies. About 3,000 workers have signed on indicating they intend to participate Saturday, according to Working Washington.

The campaign comes in response to recent pay changes on Postmates. In May, Postmates eliminated its “guaranteed minimum” pay per job, and the company also changed the base and per-mile rates for workers in some of its markets. The campaign is demanding Postmates instate at a $6 minimum pay per job for workers, in addition to still earning per-mile, base rates and tips. Prior to the May change, the guaranteed minimum was at least $4 per job.

Chris Palmer, who lives in Everett, Washington, said he’s been working for Postmates for about two years in addition to other on-demand companies such as DoorDash. He told CNN Business that the Blitz Up campaign is a “creative way” for workers to strike while still earning some money.

“The business model for these companies is to hire new people as quickly as they can – and over time, these new drivers don’t understand what the pay used to be like so they think it’s normal. It’s so scandalous,” said Palmer, who also volunteers his time to Working Washington and is helping get the word out about Saturday. “It’s not a good business model to screw the ones that are making you all the money.”

Palmer does, however, acknowledge that when blitz mode goes into effect, customers too will get a message about having to pay a surge fee. “You’ll have angry customers,” he said.

The company suggested that workers tally up the number of deliveries made over the course of an hour in order to better understand their earnings, instead of looking at earnings per delivery.

“We encourage our nationwide fleet of Postmates to express their feedback on products, policies, and standards across the platform,” according to a Postmates spokesperson. “That’s why we built our Fleet Advisory Board to make sure that individual voices are represented at the core of our company, and it’s why we are convening with Working Washington to discuss how best to balance worker protections with worker flexibility in this new era of work.”

Working Washington confirmed a Postmates representative will meet with the organization Friday.

Sage Wilson, an organizer with Working Washington, said there’s a trend in protest tactics emerging from how the apps work.

“Workers are seeing how they have power to raise their pay and they quite literally do. There’s a real strong incentive for workers to participate,” Wilson said, noting that some workers had already been using similar tactics on a more individual basis – such as rejecting jobs on platforms like Instacart that don’t pay enough.

In May, reports surfaced that Uber and Lyft drivers were turning off their apps in coordination so it appeared that no drivers were available at Reagan National Airport in Washington, DC. Fares would surge, and drivers would turn back on their apps in order to get higher fares.

The scheme is part of a growing backlash against the newly public on-demand companies, which both saw coordinated, multi-city worker protests ahead of their IPOs. The message: The workers want livable incomes, job security and regulated fares, among other demands.

Like some other gig-economy companies, the Uber and Lyft have long argued their drivers are independent contractors. That status means workers don’t get the same rights as employees, such as a minimum wage, overtime, workers’ compensation, unemployment insurance, paid sick leave or on-the-job expenses. Both companies have stated that their businesses would be “adversely affected” if drivers were classified as employees instead of contractors.

Competition between on-demand services means engaging in pricing wars, and how much workers make is the biggest cost they can control.

The workers have “certainly found a weakness in the surge pricing system,” said New York University law professor Samuel Estreicher. “If the companies let it happen, it will be a powerful tool.” But, he added, it could also “cause real damage to customer loyalty.”

“If customers leave, the company will be harmed,” he said. “I would think this is a way of harming the consumer and not just the companies, then it would be within the companies’ rights to not allow them to work.”

However, Wilson, the Working Washington organizer, noted it would be a “bad move” for companies to cut off app access for workers engaging in Blitz Up or other similar efforts: “I think they’d be reluctant to do so when the public knows why this is happening.”