This was posted by "Working Washington", so it seems reasonable to look at Washington state law: It requires tipped employees to be paid minimum wage. So does the rest of the west coast, including California (where Instacart has it's HQ).
It is, of course, entirely possible that the worker in question is not on the west coast, but Instacart is still welcome to pay a fair wage even if not required to by law, and Instacart should certainly avoid lying about their business practices either way (from the article: "Even Instacart seems to know how messed up it is to pay workers less when they get tipped more — which is why they’ve denied the practice when speaking to reporters at Business Insider & the Miami Herald.")
Washington state law does not apply. All of the State of Washington laws and constitution are fully invalidated and superseded by the American Arbitration Act.
> It is, of course, entirely possible that the worker in question is not on the west coast
The receipt was for a store named Wegmans. Those stores are located on the East coast (New York, Pennsylvania, Virginia, Maryland, Massachusetts, New Jersey).
https://www.dol.gov/whd/state/tipped.htm
It is, of course, entirely possible that the worker in question is not on the west coast, but Instacart is still welcome to pay a fair wage even if not required to by law, and Instacart should certainly avoid lying about their business practices either way (from the article: "Even Instacart seems to know how messed up it is to pay workers less when they get tipped more — which is why they’ve denied the practice when speaking to reporters at Business Insider & the Miami Herald.")