Wow, I can't believe that I'm responding to this but here goes.

The snooty etiquette lady with the advice gives bad advice. "Don't pick up your baby too much that'll spoil them", and "Naptime isn't playtime", and it's clear that mom and dad are not following this ladies' stale old advice, including in not buying the most expensive diapers out there, as they buy Luvs. So in the last scene the snooty etiquette lady's advice is: "When in doubt, overdress your baby", juxtaposed against a playful kid running around the backyard in the nude, as toddlers tend to do.