Seen them at the pool. Two ladies walking up and down the lanes with a lane rope between them. And they happened to choose our lane to do this in.
The standard rules for a lap pool is you keep left, then turn, then keep left again. Not march up and down the lane chatting to your friend. I tried to swim towards one of them to hope they would get the message, but they kept marching up and down, up and down. Obviously having no idea that they were doing something wrong, or not even caring.