I was wondering if the agent really did mail the lipstick, or merely collected a few bucks from the traveller...but it was reported in The New York Times so it must have happened as reported.
Given the security cameras pointed at airport gates, and the likelihood of Ms. My-Lipstick-Is-My-Whole-World calling up Delta and threatening to sue if her lipstick didn't arrive, I expect the agent actually mailed the lipstick.