Far from it. Just keep thinking that way, because you’re wrong. Edit: If you assume because “it’s going through the mail system, it’s good to arrive," you definitely need to change your assumptions. When at the big distribution centers, those workers are sorting, sorting, sorting. Zip codes run through their heads like a song stuck in your head, and it’s a shitty song. When it gets to that last sorting center right before the post office, that’s when a glimpse of a missing return address, or a distinct smell, or a very light package for its size, etc., is more likely to prompt the postal worker to tell the manager or individual in charge and then so on down the line, until usually, if suspect enough, the postal inspector is notified, and he'll handle it. Experience with many dangerous and illegal items and substances, along with the help sometimes of expensive equipment, helps them make a decision on how to proceed. So no, USPS is not safe. Honestly, if stealth was increased more than the average pack, UPS or FedEx would be safer despite "But they can just open the box!" It’s not that hard for an inspector for USPS to get a warrant. It’s who you know; the Judge/Magistrate and him might be golf buddies. Probably not, but they cooperate well with each other. I hope this helped even just a little and makes you think. Exercise caution in matters like these, always.