[Question] How should dance venues best protect the drinks of attendees?

In a social circle I’m in, there’s a problem now and then with people being drugged without their knowledge, via other patrons slipping drugs like roofies or GHB into their drinks. A DJ friend of mine is looking for ways to protect attendees to her shows. Besides warning patrons to be aware, are there other weird methods we might consider? One suggestion was test strips or special reactive straws, but we’ve heard there are many false positives—in particular, it sounds like acidity will set the straws off, so any drink with juice could easily trigger a false positive. Looking for other weird out-of-the box ideas to consider!