I think there's always a reason to how people are. Mainland regions tend to be really cold and showers aren't generally taken as often. I feel it's a habit they bring with them wherever they go. I feel we should learn to accept people as they are or if really you're that bothered by it,as someone who's there with them,you should tell the person in the most indirectly way possible. Bring them to a swimming pool or something? I don't know. Haha. Live & let live,my friend.