They should setup a service where you checkin your luggage, they check it for drugs or illegal stuff, they seal it, and at arrival you get your suitcase with the guarantee that it had no drugs at checkin.
http://www.theage.com.au/news/National/Bag-handler-theory-ov...
At the time, the case & defence theory was so high profile that Australian airports had a service to seal your luggage in layers of shrink-wrap before your overseas flight, so you could know if your luggage had been tampered with by baggage handlers and prevent it being "Schapelle'd":
https://www.choice.com.au/travel/on-holidays/luggage/article...
As for the TSA locks, the Prestolock TSA Search Alert locks come with a green/red indicator to show if the lock has been opened by a TSA key. Though the TSA tend to leave a notice in your bag as well saying it was opened for inspection.
It was claimed that she was the unwitting victim of a domestic airport transshipping smuggling ring, who would stuff drugs in unwitting passengers bags and pick them up at the other end. Her lawyer later admitted that this theory and the 'evidence' the defense presented around it was his invention, to the point where he was disbarred.
She claimed that she had never been involved with marijuana nor had anyone in her family. Photos and other evidence surfaced showing her smoking, and before and after her trial, family members including her mother were charged with drug offenses, including 'supply' offenses, not just possession.
Photos of her surfaced with known drug dealers and smugglers. The most damaging of these was with a drug smuggler. Schapelle claimed that the photo was from 'years ago' and that she had disavowed contact after learning of his involvement. The Indonesian prosecution showed that the photo was taken at the jail where she was being held pre-trial.
I'm not a smoker, but definitely pro-legalization. But her case was exactly that, full of conspiracy theories that had little to no backing in reality.
Baggage handler/TSA agent at airport #1 opens baggage, places drugs inside, calls baggage hander/TSA agent at airport #2 with luggage brand and traveler name.
When flight arrives, hander #2 intercepts baggage. At this point, they either take the whole suitcase, or remove the drugs and the traveler is none the wiser.