The Beer Wall, a popular bar in Bruges, Belgium, has recently installed alarm sensors on all of its beer glasses as well as a scanner at the entrance, in order to deter patrons from stealing them.

All of the roughly 1,600 Belgian beers sold at The Beer Wall are served in their own specially designed glasses, some of which are apparently very interesting.

From goblet-like glasses that usually accompany abbey-made beers, to glasses shaped like hourglasses or even sliced coconut shells, the famous Bruges bar has plenty of attractive glass artworks.

The problem is that many visitors, tourists in particular, don’t settle for feasting their eyes on these unique glasses while sipping a cold one. Instead, they steal them as souvenirs, ignoring the warnings in four languages on the bar’s beer mats, which state that the glasses are not free and that they can be bought from the souvenir shop next door.

“Every year we lose at least 4,000 glasses,” owner Philip Maes told the Het Nieuwsblad newspaper. “The tourists in particular like to walk away with them. They just take it with them without too much embarrassment.”

“In hotels people steal towels, in restaurants salt shakers and in a beer bar they steal glasses. For some reason, some customers think that when they pay for something to drink, they get the glass as a gift,” Maes added.

After seeing his profits affected by the widespread beer glass theft, The Beer Wall decided it was time for extreme measures, so he invested around $5,000 into an alarm system.

Sensors have been installed on the bottom of every glass in the bar, so if someone tries to take it out, the sensor at the main entrance will trigger an alarm. Maes hopes that the embarrassment of being caught stealing, not to mention the legal repercussions, will deter people from trying to take the glasses with them when they leave.

In case you’re wondering which of the glasses at The Beer Wall is most targeted by thieves, Philip Maes says it’s the one Brugse Zot beer is served in. That may have something to do with the fact that this beer is produced by the only remaining brewery in Bruges’ historical city center.

“Every six months we have to ask this brewery for a new pallet of 400 glasses,” Maes complained.

Hopefully, the new alarm system will at least reduce the number of beer glass thefts, although it’s not clear how easy it is to remove the alarm sensors from the bottom of the glasses, or if they trigger an alarm if you attempt to do so.