It’s always polite to give notice, even if the chain you work for is going out of business about as fast as the Pope can excommunicate unbelievers.
I used to work in a bookstore that had an incredible turnover rate - 14 people in one year - and several of them didn’t give any notice. One day they simply didn’t show up. Every desperate phone call from the boss was meant with the same calm reaction, if not a stalwart roomie.
Even though they were now at peace, it was left to the rest of the workers to suffer. It wouldn’t have been so bad had I remained hidden in the computer room or the quitters had given notice. But alas, neither of those things happened.
I spoke to some of the quitters and their objections could be divided into three groups. (A. I have said–several times-- what the problems are and no one listens to me. B. Why should I work like a dog to put money in someone else’s pocket? C. It’s just a job, man.) The last two were especially hard to argue with. Due to circumstances, the first reason was to, but there is already a group for that.