I've seen these in use in Paris, mostly by the millions of scooter commuters. It actually makes a lot of sense if you commute daily in cold and wet weather, and are not concerned with how cool you look. They usually have hippo hands on as well. When they park the bike (which can be on any sidewalk) they just pull the cover up over the seat to keep it dry. If you think these guys are wimps, you should see em split lanes everywhere! The great thing is that all the 4 wheel drivers expect it, and actually try to leave space between lanes for the bikes and scooters to fit through.
I saw the same thing in Paris as well. I thought it was a great idea. To bad no one makes them here in the US as I'd like to get one for the wife's Yamaha Majesty scooter. As for the Parisian scooter riders, they are completely insane! I stood at the circle at the Arc D' Triumph for a good 30 minutes just watching them navigate through it. They were even cutting off buses! I even saw them cut off a police car with lights and siren on!!!