I've been reading a lot of books on the subject lately and I think that's exactly how a lot street-level dealers (the lowest ranked members of the empire) are operating. The dealer would hide their product somewhere close by, for example in an empty soda can in a garbage bin or in a crack in the pavement. Once a client has made a purchase the dealer would tell the client where his stuff is hidden and the client can then go and take it.
If a dealer was busted he would never have any product on him, and the risk is relatively low if you consider that these people usually deal in units worth probably less than 20$ each. So if a package gets stolen or lost it's no big deal really.
Presumably people will want to buy drugs from a dealer more than once so it wouldn't be worth ruining the relationship. Also dealers are usually connected to some sort of crime network so it's probably a risky proposition to simply steal from them outright.
While in this case perhaps it wouldn't be to 'check it out' but certainly post purchase or whatever requirements needed to exist prior to getting the combination. It is subtle enough to blend in to an urban landscape where abandoned(?) locks on chains aren't all that out of the norm.
there’s no conceivable way i can think of to present a drug for someone to ‘check-out’ without enabling that person to steal it..