We have yard makers on our sprinklers as well, except, I don't really like to trust all of them. I've played the course so much over the years that I've pretty much memorized what club i need to use for each shot on the course. Most of them are wrong. For example, the par 3 that I live on has 3 different marks posted. On the teebox sprinkler, it says 170, on the sign saying #7, it was 135, and on the score card it says 145. It plays about 160.
However, I like those new courses that have the GPS computer's in them. They have the drawings of the course and usually give acurate markings, and they know where the pin is placed also so they provide even more accuracy. The most I have seen them off is one or two yards max. And then that course has 3 markings on each sprinkler, to the front, middle, and back of the green which is nice.
They look like this:
