My Uncle, who's been out of hunting for a few years asked to pull back my bow this summer. He hasn't hunted since the days of recurves, but I knew he knows better. Well, it slipped out of his hand and dry fired. A week before the season! Luckily, no damage, it's only set on about 60lbs. Lesson: never let anyone draw your bow, especially without an arrow.
Both the proshops around here have signs prominantly displayed saying "if you dry fire it, you buy it". I'd do the same thing if I owned a shop.