I read an article this morning that told of a Seattle dealer who carried a paper bag full of money into the King County Treasurer's Office last week to make a $51,000 tax payment, because he could not get a bank account for his pot business. That means he cannot use debit or credit cards or accept checks. All business is transacted in cast, and he regularly totes around big bundles of hard currency. Many people don't realize that banks are required by Federal Law to report any cash transaction greater than $5000, and when they do, that cash gets frozen until the investigation is complete.
Seems to me this is going to be the next big "thing" in crime...ripping off pot dealers for large amounts of cash.
Keep in mind, this is all exactly the way the State Legislatures in Colorado and Washington have designed the system to work.