I have often had items hung in the locker when flying Y. I ask with a smile if there is any room left would they mind and I get one of two answers, either "sorry it is full with J class jackets etc". or "sure no problem just remind me at the end of the flight that it is there".
What I don't like is when I fly Rouge and wear a blazer there is no locker to hang anything in.
I also endorse the folding method above. It is easier than it looks and there are a multitude of youtube videos on how to do it including this one: