I live in the country, i know what i'm talking about. If you look at the more popular gym in Sweden, they have a chain of the same gym in different areas in Sweden. Just by looking at their terms and conditions, it clearly states in Swedish ''If we suspect you of illegal drug use, we expect negative test results by a doctor within a month''
They claim they have that right and you basically agree to it when you sign up. Perhaps it's different where you live, or the guys are smart and only train during the middle of the night when the staff is gone and few people are there.