KCee How do you have a blind par 3?
We had one on a course up in St. Louis. The green was uphill 20 feet above the tee box and there was a mound in front of the green. Pretty sure the mound was a natural feature and it completely hid the green from view. They had a special flag stick that was about 15 or 20 feet long that you could just see the flag from the tee box. If you don't see the flag you assume someone is on the green. When finished putting out, whoever was replacing the flag stick would raise it up and wave it around and then replace it. Give them a minute or two to clear out and then tee off.