My experience suggests that, as long as you're using hooks and fish are biting them, mortal injuries occasionally occur. Yes, even with dry flies. However, I have personally observed fewer such injuries when I use artificials vs. bait. I'll fish bait when the situation calls for it (especially when I plan to harvest the target species), but I do think artificials are the way to go when incidental encounters are most likely. Besides all that, I enjoy the action.