I help a 4-H'er and explained to her the blade could cut toes off and such and to always put the blade back in. The first time she was cutting and jumped the ruler and went over her finger and nail bed. Took her to the ER for stitches. (Dr. didn't know what a rotary blade was.) Needles to say I went to the quilt shop the next day and bought a guard for the ruler. She didn't have any problem with coming back and cutting. She has now made three wall hangings and recieved Grand champ on each one each year. I am really proud of her.