As well ask if there are hundred-dollar bills lying on sidewalks.

EDIT: 2 days after I wrote this, I was walking down the main staircase in the library and laying on the central landing, highly contrasted against the floor, in completely clear view of 4 or 5 people who walked past it, was a dollar bill. I paused for a moment reflecting on the irony that sometimes there are free lunches - and picked it up.