The Federal Arbitration Act does not apply to “contracts of employment of seamen, railroad employees, or any other class of workers engaged in foreign or interstate commerce.” In the latest of what U.S. District Judge William G. Young called an “explosion of litigation” about Sec. 1 of the FAA, Sarah Fraga — who worked as a “merchandiser,” handling point-of-purchase displays for Premium Retail Services at grocery and big-box stores — invoked the residual clause to avoid arbitration when she filed a class action against …