The Bank Secrecy Act of 1970 was designed to detect money laundering by organized criminals. Among other things, it requires banks to report large currency transactions in excess of $10,000 to the Justice Department.
In 1970, $10,000 was a lot of money -- enough to buy a house in some parts of the country. In 2017, however, an average financially disciplined middle-class family could easily have that much in savings. This is tempered somewhat by the fact that in our modern age most large transactions are now done electronically rather than with giant bags of money.
Recently, I came into a windfall. A fat tax return, combined with money from a legal settlement, a cashout of PTO at work, a lot of overtime on my last paycheck, plus the amount I already had in savings has netted more money in my bank account than I've ever had at one time in my life. I'd like to take pictures of this event, since it's all going to pay off debt very shortly :-)
What I would like to do is withdraw all of this money in $20 bills, carry it out of the bank in a big bag with a '$' sign on it, spread it all out on my bed, and roll around in it Scrooge McDuck style. I would of course take it back to the bank promptly, because you really shouldn't have that much cash just laying around.
My question is, what kind of harassment, if any, could I expect from the government or the bank about that? Would it put me on some kind of watch list or start a covert investigation on me? Do I have to fill out any special forms (the Wikipedia article I linked to above suggests a CTR would be needed but doesn't say if the bank or the customer files it)?