In rig life you have to do the right thing to make excellent job. Focus and safe. The big problem sometime happen when not related people involve your job and think he know the job better than you.
Its make you angry.. but you cant "DING DONG" The word to say " i will punch you !!" So with this sticker at least you already warn them. Small message but make other people know.
Rig is not easy life but life in rig can make easy...