I get where you're coming from. I used to think like this too. But the thing is, if they're out to get you, you're not going to outwit them by avoiding a delivery. They wouldn't just say "oh well, we set up this complex sting involving a team of law enforcement officers who spent significant time building a case but we'll just have to walk away now.".
Add to this the fact that, particularly for "rare" crimes, LE loves to boast about arrests far and wide. One arrest and a news release will discourage thousands from doing the same thing. A lot of bang for the buck. They're not disappearing steroid users into black sites and keeping these operations a secret.
Yet find an example of what you're describing. It doesn't exist.
Read the documents in the New Hampshire lab bust from 2022 in the legal section. The feds, with unlimited resources and 3 agencies involved, just arranged to be notified when packages of raws and supplies were dropped off at the suspect's house, without signature, no controlled delivery, and then an agent stopped by the same day to talk to the perp. That's it. And that was for a major lab with hundreds of regular customers and 5000 vials in stock.
He got 3 years, btw, release to a halfway house after 18 months, and it was only that stiff because he was a 3 time convicted coke dealer.