Yes, our drinks are tampered with. Ask Morrissey about his catastrophic visit to amerikka just a few years ago.
Additionally, I might add, Kubrick is sending another message. These two, overly chummy pals are just a little too cozy. Sellers is playing with something that implies hand job. At one point the slip of paper inches upward like an erection, not an accident. While Hayden's cigar is quite obviously not, "just a cigar". But hey, you might not agree with my assessment.