salting
n.— «Secretary/Treasurer of the union David Reardon said he has authorized a number of union members to return to work slowly over the last few months and also sent some former union individuals in to apply for jobs who were then hired by Johnson Truck Bodies- a technique called “salting.” Salting allows the union to track what products are being built, where they would be delivered, and what mistakes had occurred in the process of building.» —“Truck Bodies strike: Some workers crossing line” by Jenny Miller News-Shield (Barron, Wisc.) July 25, 2005. (source: Double-Tongued Dictionary)