Removing them is a pretty painless process. Go to AutoZone, or what have you, and purchase a plastic razor, or sort of a plastic scraping utensil, and then buy some bumpersticker removal (I forget the brand name, but it doesn't hurt your paint, it's designed for removal from a car). Use a hairdryer or let the car sit on a hot day for a while, and scrape off the pinstripes (it could take 30 mins, it could take 3 hours) Afterwards, follow the bumper sticker remover instructions to remove the sticky goop that is left over.

Give the car a fresh wash afterwards and, voila! No more pinstripes.