There is no doubt that cash is a significant financial crime risk -and in relation to money laundering and the funding of future crime including terrorism, cash is king. Some governments, including the USA, have adopted a system by which banks and others are required to submit reports of certain transactions involving cash and other assets when they are dealt with. It's not as simple as it sounds.

Some of the background to this programme is in an article at World Money Laundering Report - see "How Boston benefited from a massive drugs trade"
https://worldmoneylaunderingreport.com/publications/web/educational/how… .