Scouring the rules and finally gave up, but this rules interpretation was shared with me this week during a 32 man net2 balls tournament.
With 4 guys playing, often times someone chipping up to the green will want balls on the surface (especially close to the hole), so they have the advantage of stopping the ball nearer to the hole. Forget about the purpose, but this was the situation that led to the following comments.
I asked the chipper, "do you want us to leave the balls on the surface or mark them?"
We finished out the hole when he let me know that if the chipper indicates "leave your balls there" or if any partner with a ball on the surface asks if they want it marked, then by rule - all balls on the surface MUST be marked.
First time I have EVER heard this, not sure where do locate that rule/interpretation or decision. Thoughts?