Banks and financial institutions (in the US or that are in some way regulated by the US Treasury- which in practice means everyone who uses USD, including such

Banks and financial institutions (in the US or that are in some way regulated by the US Treasury- which in practice means everyone who uses USD, including such surprising places as casinos in the Philippines) are required to make Suspicious Activity Reports (SARs) when they suspect foul play no matter what size of transaction. But only when they suspect it: not every transaction gets a SAR, but if you do, then it might be structuring no matter the size. The most notable person ensnared in structuring case is, of course, former House Speaker Denny Hastert (R-IL). He was being blackmailed to keep his sexual assaults of children secret. He went to the bank to withdraw lots of money to pay his blackmailer, and they filed a document with the FinCEN network. When he realized this, he asked about it and was told that everything above 10k needed to be filed, so he stood in line ~150 times and withdrew 5k each time. That's pretty obviously structuring, and because they couldn't get him for child abuse (because it was so long ago and the victim had committed suicide in the interim), he plead guilty to structuring.