Mysterious Straw

I was five years old, and my sister and I were visiting Grandma for the weekend. We took the tiny elevator down into the lobby and walked out into the sun. We walked under the boardwalk, passing through the striped shade on the way to the beach. I looked down and saw a straw poking out of the sand. I reached down and plucked it out. "Don't touch that!" Grandma said, "some dirty old man put that there!" I still wonder what she meant. Was it a fear of germs? Or are there old men who get a kick from licking straws and placing them in the sand each night for little girls to pluck?