Seeing these Plaketten on the snow-brushed windscreen of a SUV parked on the London Road (well, mostly on the road, but that's another story ;-) took me back to my time in Germany.
We would have to buy one of these stickers each year the first time we wanted to drive from München to Switzerland; each represents an annual toll payable to drive on Autobahnen in der Schweiz. So these Plaketten cover the years 2007, 2008 and 2009.
In my day, we usually drove to Sils Maria, a smaller village neighbouring St Moritz (and a much more exclusive one - no 'celebrity' riff-raff). I guess the driver of this vehicle is a regular skier, though I'd hate to have his or her fuel bill and carbon footprint.