Markw
Head Pro
If you are pressing down on your coin enough to the point that a ball can roll over it then you are making an indentation in the green and possibly damaging the green by you actions - extremely inconsiderate to the course and your fellow golfers.
Haha you do make me laugh, placing a 1mm marker firmly to mark a ball... 'damaging the green by you actions - extremely inconsiderate to the course and your fellow golfers'