Halloween tricks are supposed to be fun. At the end of the day, all parties involved are supposed to have a jolly laugh, but when one person is left crying, a two-year-old at that, then you’ve done something wrong. You inadvertently introduced evil into the poor child’s life, and they’ll never get their innocence back.
Also, why would anyone even steal a Jack-o-Lantern in the first place? You’re not going to put it on your porch, right? Odds are you’ll throw it in the middle of the street and laugh your stupid laugh with your friends. Shame on you.