If you are a SR buyer, encrypt your wallet and never sign for a delivery, you are fine. You can only be busted by a PI if they get you in a controlled delivery which requires a signature. And the idea that the USPS would spend resources on a controlled delivery for personal use amounts of weed or pills is laughable. If you are buying a kilo of cocaine or heroine however, expect a controlled delivery and if you don't sign, expect a warranted search of your house/apt.