An American couple – using a digital age hack to keep track of their luggage as they flew overseas for a European vacation – were left frustrated with United Airlines when one of their bags never made it to them despite them knowing exactly where it was.

But Adams’ first stop, in Barcelona, was unplanned: the United Airlines baggage office. “One bag came out, second bag came out, third bag came out, and the fourth one didn’t,” Adams recalled. Locating that fourth bag was supposed to be easy.