I've asked this question to several Swiss bankers over the last 9 years. They don't know (or don't want to tell me? 🙄 ). They claim it's the "back office" that does it with their local government and the "front bankers" don't know what is being sent.
Someone who retired from a Latin American tax office "alleges" that the information they may receive on Peter (start balance, end balance) may not be the same fields they get from Paul (start balance, Txs, end balance,︀ other bank accounts with same name etc). I find this hard to believe, but I︁ have no way of knowing. 🙄
We've asked in other countries and nobody seems to know.︂ There has NOT been one person who has inspired confidence in their "answers". 🙄
PS. I︃ do have a client that I know of ("client" as in he purchases IT products︄ from me) in the US, with a very common name, who was audited for having︅ an account in a tax haven, but it was NOT the same person. With the︆ help of a tax lawyer and an accountant, he sorted it out with the IRS.︇ It lasted ~18 months, but with about $30K in professional fees, he got to prove︈ the account did not belong to him. So, no penalty and no prison time 😉