I'm curious how much of the time people spend in a drafting pattern on tours. On a recent tour, I would say it was about 10-20%, mostly during headwinds or when riding with a slower rider and trying to catch up to the group.
I have to say though I'm really going off the practice. Once, the rider in front crashed while trying to talk to me over his shoulder, then I ride over the top of him - could have been nasty. He had a few cuts and scrapes - I had nothing. Then the next day, another near miss as the rider in front had a massive wobble. And I really don't enjoy having to concentrate so much on the road in front, hands on the brakes when there's scenery to enjoy...