The Big R stands for "RETARD" you can guess what the N stands for but ask patrick earl.
Some people who hunt for Silver coins suffer from a mental problem where they feel once they search coins they mark them because they think once they touch them and redeposit them they are out of circulation for good...this is obviously not the case.
They truly believe that these marks will somehow scare off silver coins and that there is no way that they can ever come in contact with other coins ever again, and since they are the only people who ever deal with halves it must be true. They also feel they have control over the monetary system and feel once deposited back into a magical bank that they disappear.
I have only heard of one intelligent marking system and that is to mark error possibility coins as you will get your own stuff back if you CRH for a while. It keep you from using a magnifing glass on the same coin, if you mark where say a double die is. But tahts for a few coins only. And to ones that dont have collectible value.
Otherwise anyone who marks coins to prove they come back is just a jack ass, particluarly if they have to mark every coin they touch...Dogs do this, animals do this, I put people who do this on the same level as a dog. as to most respectable CRHers