Guarding the Firewood

Marshall,
I had to go in to school to make some copies this afternoon, and when I was leaving, there was a group of kids guarding some firewood. They didn't want any big people to come and steal the wood. I didn't get the whole story, but apparently, there are people who like to steal firewood. These people must not have enough of their own firewood to make fires. Anyway, they were doing a good job guarding the firewood. Then I took their picture and they all left. I didn't understand why they left. Maybe when I took the picture of them guarding the firewood, they felt like it was safe. Any ideas?
Love you!
Uncle Mut