Reddit has an active CRH site that I visit now and then. Here is information that a CRH recently posted there (which I edited to reduce its length):
I had a job interview with a Brinks branch manager. He told me: "We don't have time to sort out silver coins and wheat pennies." An employee who worked for Brinks for over 20 years was caught putting silver halves to the side and then placing them in the wrapping machine to be put into one box. She was fired. He said that someone working at his facility who stole a silver dollar also was fired. Large dollar coins (including silver dollars) go into $1,000 bags that are shipped to the Fed where they are melted. He also said he is confident that no other branches sort silver because they don't have time to do that.
Nevertheless, I have had much better luck searching Loomis boxes for silver half dollars than Brinks boxes. I think the explanation is that in my area small local banks have a contract with Loomis while larger banks use Brinks -- and it is more likely that someone who uses a local bank will dump a coin collection that they inherit.