Or, more accurately, tellers have a propensity for taking collector coins out of circulation. I went to Riggs Bank in Georgetown, the oldish landmark on M and Wisconsin, to to see if they had any of those large dollar coins, the ones made up to 1978 before the Carter Quarter (Susan B Anthony Dollar) was introduced. I was hoping to pick up a few Ikes, maybe even one of the big old silver ones that a silver certificate would get you. But, they didn't have any at hand. They didn't check the vault, but they were sure they didn't have any. Then the senior teller came and told me, "We don't get many of those anymore. When we do, we like to keep them for ourselves. Go to a dealer to get them." So that verifies one roll hunter's suspicion. Count me lucky that I was able to get a roll of silver from a bank that one time.
Solution: go find a bank with tellers who don't know a hoot about coins, or a bank that strictly forbids their staff from doing this practice.