In terms of physiology, the color is stimulated in the brain when the eye reports input from short wave blue cone cells along with a sub-sensitivity of the long wave cones which respond secondarily to that same deep blue color, but with little or no input from the middle wave cones. The brain interprets that combination as some hue of magenta or purple, depending on the relative strengths of the cone responses.
In other words, our brains are like "🤷♂️, here's a thing"
The answer depends on the country. In the US, review the Bank Secrecy Act and anti-money laundering (AML) regulations. In Canada, there is the Proceeds of Crime (Money Laundering) and Terrorist Financing Act (PCMLTFA) regulations and also the CRA requiring the individuals and businesses retain their records for up to six years.
Very unlikely.