Generally, we go by the regs; however, we have occasionally filed voluntarily for activity that we feel would be useful for law enforcement. To add to Ken's list, some of the lower-dollar filings could also include some of FATFs human trafficking typologies (e.g. excessive backpage ad purchases). I'm sure there are other situations beyond those which could be compelling, but don't make a habit out of filing when it's not required.
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CFE, CAMS