There are QR codes put as a sticker were ever people or vendors want. Then people use an encrypted secure scanner to scan the code and deposit bitcoin to the wallet the qr code gives. Then they get a IRC chatroom or something that gives them the unique coordinates and info to find the dead drop pack they bought that's already pre set by vendors after the vendor sees coins in wallet all locally. There could also be a trusted vendor pgp and qr code verification to avoid LE setting up fake qr codes. All they could do is monitor them, but taking a qr code because your curious seems like a real stretch for probable cause. This could also be used for just everyday exchanges where the seller and buyer want no connection. Also coins can be tumbled so if vendor wallet is busted they cant get you through blockchain. People could put them hidden in headshops, or on a trail in the woods anywhere really except places where LE could catch on fast. There could even be a questionnaire to make it look inconspicuous and to deter drug war advocates. If LE bought one and tried to set someone else up it wouldnt work because he would never resell the coordinates or else he wont last and make money and he would have no rep. video evidence can be submitted at 3rd party monitored locations for larger transactions encase of scam and the funds will be returned to buyer from a multisig wallet. also the qr code can bring up 3rd party website like grams for vendor rep.
Its far too early on a Tuesday to be hitting the pipe that hard.