Is this really bad manners? It always causes such a dust cloud when I try to empty the canister into a plastic bag first and seems an environmental waste anyway.
Not sure if relevant but I live in a terraced house with not much space between the outside bins and everyone’s front doors and windows. My neighbour uses a fancy bin cleaning company to jet wash his bin in the street every so often and he was so visibly offended when he saw me chucking the dust straight in my outside bin that I thought he might pop.