When I transferred from one bank to another my account balance, using a cashiers check procedure, I was emailed by the receiving bank, asking for the reason why. I labeled the note part of the cashiers check "medical," and this seems to have been acceptable.
Whole idea of your bank asking for your used of your money seems an invasion, and once before when asked what I would use less than $10k travelers checks for, I contacted the bank headquarter to ask about this and was told it was not acceptable. My medical use of the transferred funds was more than $10k, so questionable, but not a frequent practice, still seems an invasion of privacy.
Evidently, a bank can go into your strong box and see if you're hoarding cash there, with possibly a government claim of it if you can't explain its source or freedom from taxation. Same problem if you carry $10k cash on a plane or Amtrack and it gets confiscated by police. Evidently same "invasion" if your money is found in your car or home and police seize it as evidence, or something, pending a trial over ownership. Police are good at putting "evidence" like money, drugs, guns, valuables into property rooms and never returning it to owners.