Q. In stroke play, a competitor’s ball is in a position to assist the play of a fellow-competitor and the competitor is in a position to lift the ball under Rule 22-1 without delaying the fellow-competitor’s play. However, the competitor does not take any action to invoke the Rule. Would a Committee member be justified in intervening and requesting the competitor to invoke the Rule to protect himself and the rest of the field?

A. Yes. If the competitor were to object, there would be strong evidence of an agreement not to lift the ball for the purpose of assisting the fellow-competitor in breach of Rule 22-1. The Committee member would be justified in so advising the competitors involved and warning that failure to lift the ball would result in disqualification under Rule 22-1. (Revised)

The above is from the USGA Decisions.

I have read a previous thread on this topic and am still unsure about this. I understand the person playing the chip or putt from off the green cannot ask for a ball to remain unmarked.

What onus is on the other players to mark their ball, or other competitor’s ball that may assist the player about to play?

In recent rounds I have been aware of my playing partners leaving their balls, when clearly their balls may assist the other player. I know I can request them to mark their balls but I am happy for them to leave their balls if it is within the rules.

Please advise

Assuming your ball is not involved. One fellow competitor is waiting to putt. Two other FC’s balls may be assisting.
Put yourself in the position of the RO if he were there. Do you not think that you have a duty to the rest of the field ?
The other FCs may not be aware of the rule (that they may lift their ball). If they are, then the decision above applies IMO

I think that the “decision” confuses people – if A is substituted for competitor – the decision then reads:

In stroke play, A’s ball is in a position to assist the play of B and A is in a position to lift the ball under Rule 22-1 without delaying the fellow-competitor’s play. However, A does not take any action to invoke the Rule. Would a Committee member be justified in intervening and requesting the A to invoke the Rule to protect A and the rest of the field?

A. Yes. If A were to object, there would be strong evidence of an agreement not to lift the ball for the purpose of assisting B in breach of Rule 22-1. The Committee member would be justified in so advising the competitors involved and warning that failure to lift the ball would result in disqualification under Rule 22-1. (Revised)

I would love somebody else’s opinion here. This is a situation that happens in every group every weekend. How about some feedback!

Since you asked;the decision is really quite clear .You really should mark your ball if it is assisting one of your fellow competitors.
Very unlikely that someone external is ever going to enforce this unless you are playing in some really important event that has roving officials.Just seems like a matter of basic integrity to me and it’s something that I always do , in fairness to the rest of the field.Others may feel differently.