Retail marijuana stores have to deal in cash, as most major banks refuse to deal with them. This causes a very dangerous situation for the store owner, and stories are already circulating about the vulnerability of having so much cash on hand. However, it doesn't seem to be illegal for the banks to accept funds from cannabis shops, but these banks can be expensive and burdensome. Can a retail marijuana shop bank from a locally owned bank outside of their state to handle credit card transactions? In other words, can a retail store in Colorado bank with Maps Credit Union in Oregon, or even within a state that hasn't legalized recreational use?
This is an interesting idea, but very risky for the bank. Oregon and Washington's truce with the Feds involves strong state backing, banks willing to take risks that no Colorado bank has been willing to take, and a tacit understanding that the Feds will tolerate this because the banks know their customers and are very familiar with their state's regulatory regime so that they can distinguish between "marijuana limited" and "marijuana priority" accounts in their FinCen reports.
People in the industry (I represent quite a few in Colorado) are always looking for solutions to the banking issue. But, due to a combination of personalities in state government, the banking industry, the local branch office of the Fed, and so on, no one has managed to make that work in Colorado and federal government authorities are very primed to give a great deal of scrutiny to interstate operations of any kind.