Originally Posted by Dovster

If you do not enter Swizerland on the autostrada you will not have to buy the sticker. It is not required for use on regular roads.

You are, of course, subject to a fine if you later get on the autostrada but no Swiss policeman has ever gotten close enough to my car to see if I have one. Just make certain that when you leave the country you also go through a non-autostrada road.