This story concerns Zeno Vendler, late of the University of California at San Diego:

Bela Szabados, who received his M.A. under Zeno in 1968, recalls an incident in the late 60’s during a rally organized by the students’ union to protest the Vietnam war. There was a small group of speakers from the US to speak about the war. Some Philosophy graduate students wanted to hear what they had to say, and showed up with Zeno in attendance. As they gathered, they were asked by police: "Are you the Group?" Zeno turned to them and said: "Well, we do form a group," whereupon he was arrested. He was released only several hours later.

Thanks to Alan Thomas (Philosophy, Kent) for the pointer.