I know you guys order your stuff by mail, but here's how it's mostly done in Russia: the vendor hires people to hide the packages somewhere in the city (i.e. rain pipes, benches, rocks, holes in buildings) and after you pay, he gives you the location with a detailed description of where the package is hidden (sometimes with a photo). Do vendors in other countries do this? And is there a name for this?
It's a "dead letterbox".
Drugs aren't left there for long. An hour at most.
You get the customer in the general location waiting in a pub or somewhere, set up the dropspot, then tell them the location via encrypted messenger well after you've left. taped under the toilet brush holder in a toilet stall of a nearby bar or somewhere the customer can recover it unobserved.
Its halfway between the darknet and IRL dealing, and its only for special circumstances.
When telling the customer where to be, and at what time, you may use the old spy trick of "honest to god" time.:-
If I tell you to be there at "10PM, honest to god", I really mean 3 hours earlier ie 7PM. Any eavesdropper would turn up well after I and the customer have both gone home.