You missed their point. It's cash on the barrel head or counterparty is presumed to be a scammer. If you follow that rule you'll never be scammed.
until you get robbed, kidnapped or forced to do a bank transfer.
At that point, nobody cares if you were trying to steal the silverware.
what law? In my country in my scenario the person would be charged for scam (fraud), robbery and any other possible crimes.