But why? I wear it round my waist under my hoodie so there is zero chance of it coming off. As long as it's clipped in place it should be fine. Having a bum bag strapped properly and tightly round your waist is no different to having a watch strapped to your wrist. Over the shoulder ones yes, they should be removed. Before they worry about safely strapped bum bags round your waist, they need to be more concerned stopping with those idiots who sneak out their phones or small go-pro type cameras once the train has left the station.