A seller needs to know when he offers his property for sale, if he has an exemption or whether he will pay capital gains tax. When an offer comes in, it will usually say that both buyer and seller agree to their usual closing costs. For the seller, capital gains tax is an expense.
The September 11 attacks in 2001, which led to the Patriot Act in the US and similar legislation worldwide, led to a new emphasis on money laundering laws to combat terrorism financing. The Group of Seven (G7) nations used the Financial Action Task Force on Money Laundering to put pressure on governments around the world to increase surveillance and monitoring of financial transactions and share this information between countries. Starting in 2002, governments around the world upgraded money laundering laws and surveillance and monitoring systems of financial transactions.