THE APP ECONOMY: Travelers Cash In Using International Delivery Apps, Often By Skirting Customs Duties.

San Francisco-based Grabr—which says it has more than 500,000 world-wide registered users—offers a web platform allowing shoppers to request international deliveries. The company, backed by big-name investors including Peter Thiel’s Founders Fund, is popular in markets such as Brazil and Argentina, where foreign goods purchased locally are expensive.

Many goods are a vastly better deal for Grabr shoppers if their traveling partners don’t incur any duties on arrival.

The Wall Street Journal interviewed more than a dozen Grabr travelers, almost all of whom said they tried to bring expensive items through customs without paying duties.

“I would take the items out of the boxes to make them look used,” said former deliverer Evelyn Slater-Shew, 27 years old, of Long Beach, Calif., on how she would avoid customs when transporting goods.

Ms. Slater-Shew said she delivered items selected by Grabr staffers who appeared to know “what we were doing” and advised her to “make everything look used or old.”

Sneaky.