My dorm in college was across the street from a house that student groups could use to hold meetings and host speakers. Once the campus animal rights group had a guy who had apparently done some high profile, yet illegal, work related to animal releases decades earlier.
I happened to be in the lobby of my dorm when two uniformed cops were introducing two plain clothes cops to some people affiliated with the university. The cops were there to blend in and go into the meeting to watch this speaker and find out if he was planning on recruiting or doing anything illegal. The problem is that the cops looked like they were going undercover in a biker gang. They were both 250 lbs, dressed like the just got off work at an auto garage, and in their 40s. They didn't exactly blend in with every single other person going into that meeting house who were early 20s vegans and vegetarians. At least the cop in this story fit in a bit better.