According to the Financial Action Task Force (FATF), the use of large amounts of cash is a common method for money launderers to move illicit funds [1]. Purchasing luxury items with cash can indicate an attempt to convert illegal funds into tangible assets that can be easily resold or moved across borders. As a result, businesses that deal with luxury items are required to implement enhanced due diligence measures, including monitoring transactions involving large amounts of cash [1].
Reference: [1] Financial Action Task Force. (2013). Money Laundering & Terrorist Financing Through the Real Estate Sector. https://www.fatf-gafi.org/media/fatf/documents/reports/ML-TF-through-real-estate.pdf

The Egmont Group assists financial intelligence unit members to accomplish their goals by providing support to expand and systematize cooperation related to the reciprocal exchange of information, fostering better and secure communication through the application of technology, and encouraging operational autonomy of financial intelligence units. Additionally, the Egmont Group also maintains uniform global formats for funds transfers that assist in the detection of money laundering and supplies information on the common money laundering tactics used by terrorists and financial supporters of terrorism.

Explanation/Reference: http://fraudaid.com/Dictionary-of-Financial-Scam-Terms/black_market_peso_exchange.htm