Early in the morning on June 18, a message from an unknown account slipped into the TikTok inbox of a flight attendant in Bangkok with a series of questions: “Are you flying to Australia? Do you do carry-for-hire? What is your rate?”The 30-year-old, who flies for a regional budget carrier, ignored the message and forgot about it – until Tuesday, when a Thai Airways flight attendant was charged with importing more than one kilogram (2.2 pounds) of heroin into Australia hidden in several tote...