Fortunately, there was an FAA inspector onboard who was seated in C, witnessing the ordeal. When the pax failed to comply with the crewmember instructions by the 4th request, the FAA inspector intervened and gave the couple a ticket for "Failing to comply with Crewmember instructions, and Interfering with a Crewmembers duties.
I often wish there were more FAA inspectors onboard that would give tickets to those who fail to comply, or blow off the FAs, but then we wouldn't have enough seats for regular paying pax who do comply
