I rarely use my pedal wrench anymore and usually just go with the hex key. I've never had any trouble, although I do have my pedals on and off fairly often switching my favourites between bikes. Don't forget those pedals were put on with a key too, so they won't be as tight as normal anyhow.
If someone did strip the hex you could always go the ez-out route (well, on the rh pedal at least.) Same argument if you round off the flats on a standard pedal anyhow...