Earlier quoted context omitted.
Two things: (a) Banks can be vague in their SAR filings with “transaction with no apparent economic, business or lawful purpose” (b) What BSA manul says: "No bank, and no director, officer, employee, or agent of a bank that reports a suspicious transaction may notify any person involved in the transaction that the transaction has been reported." [1] This deadly combination is enough for banks to NOT disclose. That's…
The manual says that customer should not be informed for the reasons of reporting. But it doesn't say the banks should close the accounts.
One way to avoid getting out of this trap is to join the club of "private banking" services provided by big banks. It is like Airline's first class vs. economy class customers. Banks put different resources for private banking clients such as: (a) manual override by humans (b) reduce false positives by algorithms by tweaking parameters (c) specialized representatives, cust service folks.