Because my baby didn't have shoes on. See, there's a "shoes must be worn at all times" policy in the children's room of the library. There are signs posted and I was aware of it. Earlier in our visit I even re-shoed Jonas who had taken his off as he sat down on the floor do do a puzzle. I reminded him "We wear our shoes in the library."
But Wyatt (who would have normally had shoes on, but Jeremy had prepped him for the outing, and most-likely not knowing that the boys and I were planning to head to the library after dropping him off at campus was unaware that Wyatt probably needed shoes on, and therefore he did not have shoes on) was toddling around and caught the attention of a passing librarian.
"He needs to have his shoes on." She said while looking at me. I was picking up a basket of books that Wyatt had knocked over, and hadn't responded as she continued to look at me with her eyebrows raised. As she was obviously waiting for a response I answered in a plain tone, "He doesn't have shoes."
I then picked him up and sat down with him on a floor chair and nursed him. Thus proving my point to the library gods that: he's just a baby. I was aware of the rule, and ordinarily would have not been operating outside of it, but I really didn't think it was that big of a deal for a baby to not be wearing shoes.
(He actually does have shoes.)