With the number of foreign tourists to Japan increasing by the year, authorities are warning visitors to steer clear of so-called rip-off bars.

Such establishments have been a problem for a number of years but police are no closer to being able to shut them down, with many operating in a gray zone that protects them from prosecution.

The U.S. Embassy issued warnings about such establishments in 2014 and again as recently as 2017.

“We remind U.S. citizens to exercise caution and maintain security awareness in entertainment districts like Roppongi and Shinjuku’s Kabukicho, as drink-spiking incidents over the years have routinely led to robbery and occasionally resulted in physical and sexual assaults,” the U.S. Embassy said in a statement in 2014. “In most drink-spiking reports, the victim unknowingly drinks a beverage that has been mixed with a drug, rendering the victim unconscious or dazed for several hours, during which time the victim’s credit card is stolen or used for large purchases. Some victims regain consciousness in the bar or club; other victims may awaken on the street or in other unknown locations.”

Whether a victim is drugged or not, the chain of events is typically the same. They’re lured into an establishment by a street tout (kyaku-biki) and charged exorbitant prices by the operators, usually under the threat of physical violence if they refuse to cough up the cash.

Customers are often escorted to a nearby ATM and instructed to withdraw the amount owed.

If a customer is unfortunate enough to have been drugged, they’re obviously in no fit state to argue. It can also be easier for the bar operators to get money out of them, forcing them to sign credit card bills that can amount to tens of thousands of yen without even having to make the trip to an ATM.