.... one was an undercover cop.
How did you find out? 
They're so obvious at concerts and festivals. Here's a typical example: Dirty white tennis shoes, tight jeans, tucked in t-shirt, forward facing baseball cap, a cellphone belt holster, looking around nervously, and asking groups of people, "Hey, do you guys know where I can find some [insert drug here]?"
I respect police, but come on guys, you can do better than that.
