One of them refused to pay additional fee for luggage
All of that mess over several euros for luggage?
Kind of reminds me of a certain idiot Polish politician who having paid for an economy seat tried to start a riot on Lufthansa plane because they would not let him put his coat in first class. Yes, its true. And it shows how ignorant the public is of both laws on books and potential for massive harm in these kinds of situations.
Like others, I detest being a passanger on a commercial airline, but people have to understand there is no way to avoid the cattle wagon experience unless people are willing to pay several times more for tickets – and they aren’t. There have to be stiff penalties for things like that because any disorder with that many people cramped into small space is disaster waiting to happen. Crowd stampeding/suffocating each other to death in panic is not exactly an unheard of issue.