Casinos on Cambodia’s border with Vietnam are seeing fewer gamblers after Vietnamese authorities imposed tougher border crossing rules. Vietnam’s Ministry of Public Security said it was responding to increased reports of its citizens being held hostage or even killed after gambling at Cambodian casinos.

Such lurid reports aren’t new. But investigating these cases can prove difficult because, as Ministry official Vu Hoang Kien told Thahn Nien News, the victim’s families are “often too scared to report honestly, if they decided to report to police at all.”

There are 54 casinos and 36 cockfighting pits along Vietnam’s 789-mile border with Cambodia. There are 24 different border gates through which over 1.6m Vietnamese traveled in 2014. Around 234k of these are believed to have made the trip for gambling purposes, while police say others are suspected of loan sharking for Vietnamese clientele while in Cambodia.

Recent “determined actions” to tighten border crossings have staunched the flow somewhat at certain crossings: from 500 people per day to just 100-150 at Tay Ninh and from 1,500 down to 500 per day at My Quy Tay in Long An province. Most of those crossing the border claim to be going for tourism, when all that lies across the border is, in the words of Vietnamnet, “wasteland and the casinos.”

The crackdown has led to a lucrative side business for ‘brokers’ who either guide Vietnamese gamblers across the border via backwoods trails or who pay border guards to look the other way. Kien believes the failure to control the border is the result of poor bilateral cooperation between the two countries.

Or maybe things are going precisely as planned. Back in 2012, Cambodia prime minister Hun Sen told his nation’s parliament that border casino construction had been a “secret strategy” to prevent any potential invasion by Vietnam. “One can remove border markers, but one can’t remove five-story hotels.”

For some time now, Vietnam has been making noise now about lifting its longstanding ban on letting its locals gamble in casinos in their own country. The Grand Ho Tram Strip has bravely offered its facilities for a pilot project but Vietnam continues to stall. Cambodia has suggested it would be forced to follow Vietnam’s lead rather than seeing the current situation reversed, i.e. dealing with media horror stories of kidnap and murder of Cambodian citizens in some other nation’s den of iniquity.