From a Streetsblog tipster:
I was riding my usual route home from work, which includes a left turn from Broadway onto 17th St., when I spotted a medium sized crowd outside of the Union Square Barnes & Noble. I remembered that Bill Clinton was scheduled to appear there, and figured it must be him. I turned toward the crowd and was surprised I was allowed to ride right up to it and dismount. As I approached, I spotted that recognizable silver hair and ruddy complexion. He was making his way up and down the crowd, shaking hands. I tried to think of what kind of exchange I might get to have with the former President that would be more meaningful than a handshake. Happily, I remembered that I was displaying on my shoulder bag my banner that reads, "cycling is good citizenship." I held it up over the heads of the admiring crowd for Bill to see it. As he made his way past my spot, I saw him squint a bit to read the sign, and then, he said with a smile and a finger pointed at me, "I agree!"