"Mong Kok is an area that has been traditionally very influenced by the triads," Degolyer said, noting the neighborhood is densely populated and has many small, locally owned shops.
"There are also a number of house brothels that the triads control – and there is tourism and bars that they influence and collect protection money from," he said.
Read More Hong Kong protests dwindle, but talks with government likely to go nowhere
Many analysts have attempted to estimate how badly the protests have hurt Hong Kong's tourism and legitimate businesses. Cosmetics retailer Sa Sa said Wednesday that its same-store sales for the Golden Week holiday fell 3 percent from the year-earlier period, compared with last year's 6 percent rise.
But quantifying the hit to organized crime is difficult.
"The triads don't exactly file annual company reports," David Yang, an analyst at IHS, said via email.
Yang noted the Hong Kong Travel Industry Association reported the territory has lost more than 200 mainland tour groups a day over the holiday, but since these groups tend to be family-oriented, they wouldn't affect illicit business much.
To be sure, data from the Hong Kong Tourism Board indicates the arrivals in Hong Kong from the Mainland over the Oct. 1-7 holiday period were up nearly 7 percent from the year-earlier period.
Read More Anger simmers in Hong Kong after protest camp attacks
"People who patronize bars, night clubs, massage parlors, etc. tend to be free individual travelers (so-called 'FITs'), and the number of individual travelers has not been as seriously affected," Yang said. He also doesn't believe the protests are affecting money laundering options much.