I had an interesting situation come up recently. My ball was just off the green and putting was the only real choice. Directly in my line was a sprinkler head, also just off the green. Our caddies, all of whom were St. Andrews University students, agreed that since the sprinkler head was within 2 club lengths of the green as was my ball, I should get relief. First time this has ever happened to me and I just accepted their interpretation.
I was vaguely aware of a recent Rule change related to greens and sprinkler heads but had not ever had occasion to figure out how to proceed. It was nice having the caddies walk me through the process. Hope they were right!