Moncheri -
Here's what to do...walk into your bank with a large bag of money, preferably bundles of $100 bills. Wear dark sunglasses. Act nervous and whisper when you talk to the teller....
(Sorry, couldn't resist!)
Many of the above suggestions have been good, however, I don't think most of us would feel comfortable taking the bank manager out to lunch. Perhaps if one is a business owner in the area, but for most of us, it would be awkward and unrealistic, and actually, IMO, would make them wonder what our real agenda is. That being said, it is good to become a familiar face where you bank.
Most of all, have accounts at at least 3 or 4 different banks, so you won't be doing large transactions with any one bank.

GrahamB.....the question here is not about avoiding paying taxes, but rather avoiding being on the radar...two entirely different issues.