What do you mean? As long as people inspect what they are transporting or only take things delivered to them directly from merchants, I don't see how this would be a problem.
In fact, there is a whole class of travellers in some parts of the world now called runners who do this
How would you inspect it? I don’t think you have a good chance of finding hidden drugs, but the airport might. So there’s a risk that you missed it but their dog will find it, and you’ll be on the hook.
The runners i am referring to either receive orders from merchants like Amazon or Apple then bring them for people, or they buy the items themselves once you give them for the items you want. That way, they minimize risk. If I am not mistaken, if you want to send things like documents, you have to courier with an official courier like FedEx, UPS or DHL then you have to allow them to open the envelop to ensure it is only what is listed then they transport from there.
By the way, this service for travel between countries. So people who want things from the US, Dubai or other large shopping destinations and when it is the reverse direction, where people in the large countries want things from back home countries like certain foods, ornaments etc, then they have to give the runner the money and the runner makes the purchase.
I expect it to make a huge difference if you go out of your way to say at the earliest opportunity : "I am (also) a courier, please check this item (that doesn't belong to me)."
Literally every check-in form I've been through had some required checkboxes to declare that you've packed your luggage yourself, have complete awareness of what's in there, and claim responsibility for such items. There are also countless, very visible, posters in airports saying so. Your paper trail might be useful to law enforcement in prosecuting the people who handed you the no-no stuff, but it doesn't absolve you of any responsibility.
Anecdotally, I once had an outrageously difficult time explaining to a German customs officer that the bag I placed in the scanner had items belonging to both my sister and myself. It didn't help that we were travelling together, and she was also there to back my statements up. He simply would not accept the fact that there was an electronic device (e-book) that belonged to her, in a bag that belonged to me, which we forgot to take out before the scanner.
That's not how the world works. You are responsible for the luggage you are transporting even if it's not yours. The customs do not care and they are not going to try to figure out the laws of the place you came from or get in contact with their authority.
> The customs do not care and they are not going to try to figure out the laws of the place you came from or get in contact with their authority
Yes. They also won't try to 'interpret' their own country's laws, it's above their paygrade. If you aren't doing exactly what they expect, they will hold you (or your passport) and push the issue upstairs.
Source: I had this happen to me when I tried to enter Canada to work on a contract for which I should have had a work permit. My company had given me the paperwork appropriate for a salesperson or conference attendee. The officer at the gate confiscated my passport, told me to come back the next day with the correct paperwork, and threatened me with arrest if I failed to return. Stress and long nights ensued.
Yeah, and if the perpetrators have disappeared, the authorities aren't going to say "Oh well, they disappeared, let's hunt them.", but they'll drag the mule into court instead...
Depends on the country, I wouldn’t try it myself. And I’m pretty sure „well I wasn’t even allowed to inspect my luggage, i have it on paper“ isn’t a good defense, because then you shouldn’t have taken it in the first place. If you bring something onto a plane, it’s your responsibility. If you don’t know what it is, don’t take it.
In fact, there is a whole class of travellers in some parts of the world now called runners who do this