I said it way back on the old site but it's probably gone now, nothing stops literally anyone from mailing you anything. I could be wrong because I'm not every state and I've obviously never been CD's myself, so someone correct me if they know better. You simply accepting the package doesn't claim ownership, whatever entity prosecuting you would be using things they found in your house to prove you were intending to use the drugs or distribute them (like mentioned above, they'll have a search warrant for your entire house).
I think people are kind of going a little above and beyond sometimes when they say they leave their pack out on their table and write 'return to sender' all over it. If it gets far enough that LE is seeing the package they most likely are going to see all the shit you use to inject with anyway, and claiming it wasn't for you is going to get real hard regardless of whether or not it looks like you were going to send it back/take it to authorities.
At the end of the day you wanna do a thing, and that thing has consequences. I like to ride my motorcycle without a helmet a lot because it's more enjoyable, yet I recognize the risk I'm taking when I do it. A lot of people used to smoke/sell pot in school but they found the benefits outweigh the risks.
Coming from someone that's been inpatient for extended periods of time at psych facilities, I'd much rather be locked up than not live my most comfortable, enhanced, and best life. I have a script for TRT, but UGL homebrew is still insanely more cost effective so I take the risk. I also took my time and got to know what happens when people get busted and yeah, like mentioned above no one really gives a shit about a juice bro cycling unless they're doing dumb shit like leaving needles around or beating their wife.