I report runners who agree to a set number of ends and run after scoring in the first end with the hammer. That to me is unsportsmanlike and if you agree to the number of ends, then... run... off that's cowardly.
If people don't like being called a runner... they shouldn't run.
It's no problem with me, my rating has dropped like 100 points in the last couple of months but as long as I have a nice opponent, I don't care about the rating.
Heck, I've lost 10 points in like 4 different ends playing skins, none of that bothered me, I was out played every time.