Touching someone else's ball marker

[North Mimms]

I did this a few days ago in a casual game with my husband but afterwards wondered if I had broken any rule....

He marked his ball on putting green then walked back to front of green to repair a pitch mark.
I bent down to look at line of my putt and realised that his marker was sitting up a bit, not totally flat on the ground and on the line of my putt.(It was late in the day on a warm Florida afternoon so the green was getting fluffy)
If it had been a serious comp, I would have asked him to move marker to one side, but instead I just leaned forward and lightly pressed it flat.
OK or not?

 

[palindromicbob]

16-1a
The line of putt must not be touched except:
(i) the player may remove loose impediments, provided he does not press anything down;
(ii) the player may place the club in front of the ball when addressing it, provided he does not press anything down;
(iii) in measuring – Rule 18-6;
(iv) in lifting or replacing the ball – Rule 16-1b;
(v) in pressing down a ball-marker;
(vi) in repairing old hole plugs or ball marks on the putting green – Rule 16-1c; and
(vii) in removing movable obstructions – Rule 24-1.
(Indicating line for putting on putting green – see Rule 8-2b)

All is fine even in the land of rules. Notice it says a ball marker not their ball marker.

Although in practice it would be better to either get the player to move it or request permission to press it down if match play. Reason being. If you accidentally move it while pressing down and have asked permission to do so there would be no penalty. Had it moved and you did not have permission then you would receive a 1 stroke penalty. This is basically applying the rules regarding ball at rest moved by opponent (18-3b) to the marker under equity (Rule 1-4) Decision 20-1/6.5.

Expanding this principle then in stroke play the ideas of Rule 18-4 would apply. As the FC the marker would need to be replaced with no penalty.