Note how Curtis Green was raided: they delivered some drugs, then searched his house on the grounds that he was in possession of drugs. This is a standard US Postal Inspectors tactic: it was used many years ago (see http://totse.mattfast1.com/en/law/high_profile_legal_cases/a...) and it looks like it is still being used.
If you are thinking that this looks like an end-run round the fourth amendment, then you have been paying attention.
If you are thinking that this looks like an end-run round the fourth amendment, then you have been paying attention.