Many moons ago I watched a TV show like "candid camera" on a German TV Channel.
They had a B737 for maintenance at Hamburg, all seats removed. So the TV team installed a pair of handrails at the ceiling of the 737.
At the gate they offered a fare reduction of DM 50.- to fly almost two hrs to Mallorca, no seats, standing up in the cabin.
Only three of about 140 pax refused.
All others got on board, laughing.