While we are on this topic let me add by saying, I see different colored (green,white,red) round circles on the fairways all the time, looks like manhole covers to me. Or is this a virtual yardage detector to see how far you hit your ball?
Also have seen some green and at times black curved pipes comming out of the ground as well. Is this irrigation pipes installed like the real courses have?
Just as long as It does not hinder my playing if I accidently hit one with a drive off the tee or fairway I'm ok with it.
:) Joe