I got the Crafty Fab and stuck the stickers on that and they are waiting in my glovebox until I need to stick them on. I rarely am alone in the HOV so it won't be very often and this Crafty Fab is the perfect solution! I can't remember who mentioned them to thank, but here is the link to pass on the goodwill.
Amazon.com - Crafty-Fab by Vinyl Oasis - Self-Adhesive Craft -
That's a great idea.