And the problem with marketing to children is... nothing.
The fault lies parents who are more interested in being "friends" with their kids than their parents.
@4: There's a whole branch of advertising aimed at how to most effectively get kids to nag their parents. They differentiate between different kinds of nagging (pleading, bargaining, threatening, repetitive, etc.) and which have the best effect at getting parents to give in and buy the item. Have you ever been a parent? Or have you ever dealt with younger siblings?
The fault lies parents who are more interested in being "friends" with their kids than their parents.