Cross Pollination?

There is a limited amount of silver left "out there". With the various CRH'rs roll hunting as well as the occasional teller, cashier or customer finding them the number is ever decreasing.

Occasionally the amount of silver spikes in a small area as a collection gets dumped by a thief or out of ignorance. These coins could stay local or get sent to another area if there is a need for that style coin elsewhere.

Usually when you find several silver coins in a roll or even a box it is due to a collection dump, otherwise you will likely find a single silver coin here and there, often going several boxes between them.

In an area with active hunters the silver dries up rapidly and the same set of scud goes round and round. Some hunters mark their scud, the advantage of that is that you can get a read on the cycles. Of course a lot of people hate that a coin is marked, even if it isn't collectible. (There are tons of threads on marking out there...)

CoinStar and the like kind of change the dynamics a bit, it makes it easier for people to dump collections. They do tend however to reject silver coins but I am sure plenty make it through anyway.

being North of the border, there are slight differences in the system, I think there are only 2 Churchill, and another, however this is not the issue for me, because I don't count machine wrapped rolls, for us these are 95% of the time all post 2002 coins and contain nothing (I call these Junk rolls).

Up here the Mint has something called the Alloy Recovery Program (ARP), so coins going back get searched and older coins get melted down (pre 2000)

most if not all of my pick up banks give me only CWR, so these have not been to a redistribution center.

As to marking your dumps, I have seen this, but not in that specific area. Also I don't mark my coins, or wrappers so I would not know if I was getting mine back or not. However I did start marking boxes of coins, when I take them back, just to see if by chance I get one back.