he move against the junket organizers last week suggests a broadening of the investigation into Crown and comes after an explicit warning from Chinese officials in Macau just three months ago.
The China Liaison Office, Beijing's representative in the former Portuguese Colony, said in a meeting with the Macau Gaming Information Association (MGIA) it was concerned about illegal money flows and that large gamblers were being allowed to bet on credit.
"For more than a year the industry has been warned to pay attention to China's anti-corruption campaign," said Tony Tong, founder of Hong Kong-based risk management firm Pacific Financial Services and vice chairman of MGIA
The detention of junket agents, who find and bring Chinese high-rollers to casinos and lend them money to gamble, provides the strongest indication yet authorities are not just targeting Crown's marketing activities on the mainland, but also investigating money flows to casinos in Australia.
"The illegal movement of funds has come up repeatedly in discussion with the lawyers," said one family member of the detained Crown staff.
Under China's strict capital controls, individuals can only move $US50,000 out of the country each year.
One industry source said two junket agents, who worked with Australian casinos, had attempted to flee from Shenzhen into Hong Kong soon after news of the Crown arrests broke but were stopped at the border by police
"These agents had business in Australia," said the source with knowledge of the detentions.
"It is not just the 18 Crown staff who are detained."
The Australian reported that 10 junket organisers connected to Crown had been detained across China and 87 questioned by police.
"The government is sending a clear and loud message to the gaming industry about the prohibition of marketing activities in China," said Mr Tong.
Crown has faced heavy criticism for not heeding repeated warnings that its activities on the mainland were coming under greater scrutiny by Chinese authorities
Along with warnings about providing credit and facilitating illegal money flows, the casinos were warned about taking government officials, their spouses, children and friends on paid tours or golfing holidays.
"There is an awareness from the government that marketing activities by gaming companies on the mainland have become more subtle," said Mr Tong. "They are not promoted as gambling trips, they are promoted as tourism trips."
The Chinese authorities were reportedly worried that problem gambling was causing "social disharmony" on the mainland and it was becoming a "financial drain" on the country.
China's currency, the yuan, has come under heavy pressure this year as the economy slows, forcing the central bank to run down its foreign reserves to prevent a sharp devaluation.
The 18 crown employees are facing up to 10 years jail for "gambling crimes", although this maximum sentence has not been imposed in recent cases.