This Just in: Parents realizing it is a bad idea to give children their iTunes password

"Arlington second-grader Leyla Ulku figured out her parents' password and recently racked up a $150 charge from buying buckets of stars and snowflakes to build a safari out of sea turtles and giraffes on Tap Zoo."

-Gizmodo

Clearly, not the best idea. Note, when you sign up for an iTunes account, there is an option to not enter a credit card and to only allow paid application purchases when you enter a gift card.