[Ken H]

Drug War closed that option decades ago =>

The Bank Secrecy Act of 1970 (or BSA, or otherwise known as the
Currency and Foreign Transactions Reporting Act) requires financial
institutions in the United States to assist U.S. government agencies
to detect and prevent money laundering.

Specifically, the act requires financial institutions to keep records
of cash purchases of negotiable instruments, and file reports of cash
purchases of these negotiable instruments of more than $10,000 (daily
aggregate amount), and to report suspicious activity that might
signify money laundering, tax evasion, or other criminal activities.

http://en.wikipedia.org/wiki/Bank_Secrecy_Act

[BlackElk]

I do not accept the notion that because some people want to alter or obliterate their consciousness with various drugs and others profit from their stupidity, that somehow the government is entitled to compromise the privacy of the entire population.

The Bank Secrecy Act of 1970, as you describe it, is one more useless nosy, busybody, unnecessary law that ought to be repealed. In fact, it would be a good rule for Congress to live by to require 10 laws to be repealed for each new one enacted and to prohibit "Christmas Tree" bills altogether.