The tragedy in Crans Montana was preventable
Sadly the mass loss of young life in the night club in Crans Montana is not the first such tragedy, with PBS collecting some past examples: https://www.pbs.org/newshour/world/a-look-at-some-of-the-worst-fires-in-bars-nightclubs-and-music-venues There was also this one in Rouen, France: https://fr.wikipedia.org/wiki/Incendie_du_Cuba_Libre. The similarities are striking