According to John Cedars' website,
Chile has a special two-day national celebration, known as Fiestas Patrias, on September 18th and 19th. On these two days, ALL public buildings are to display the national flag, either on a flag pole or otherwise adorning the front of the building. Any institutions that refuse to show the flag do so at the risk of paying a fine.
Though reportedly some congregations would rather pay the fine than display a national symbol on a building dedicated to worship, it seems not all the bodies of elders in Chile see it as a problem.
Some have suggested that the disparity has been caused by congregations being instructed by the branch that they can decide for themselves whether to show the flag or not, but that if they refuse to show it they will be liable themselves for paying any fine. This has yet to be verified.
If it were in the U.S., they could tell the authorities that the building belongs to Watchtower. I don't know who owns the building in Chile.