One problem is "related" is not defined. I owned a bar and had cash deposits that never came to $10,000 a day in the first 6 or 7 months we were open. After about 2 weeks of deposits in the $2,000 to $3,000 per day range, I was turned into the feds by a teller. I would have never known except a junior bank officer was married to my cousin and told me about it.
About a month after I was turned in, the ABC came around and did an audit and the IRS came the following week. I passed both because I always over pay a little bit just to be safe. However, it was a major pain in the butt and silly.