How many times have UPS or Fedex agents kicked down the door of someone who ordered drugs to send them off the prison? Do you think that Fedex is going to spend their time and money trying to intercept drug packages and arrest the people responsible for sending them and receiving them, if the government does not force them to do so? Of course not, they are a shipping company not a fucking drug enforcement company. Anyway mail through customs can be inspected without any warrant at all, that only applies to domestic first class letter mail. Government is not protecting us by not searching our mail without a warrant, they are the fucking aggressor we are forced to need protection from in the first place, not Fedex and not UPS. Private mailing companies will of course have contract that they need to follow with the customer, and anyway if Fedex decides it doesn't give a fuck about making profits and want to enforce a ban on shipping drugs you find a new shipping service. If Fedex decides it wants to get into the slave trade or into robbery business and target those with drugs, your private defense agency attacks them and defends you until the aggressor is defeated to the point that they leave you alone and repay for all damages. Nobody is promised to win be they right or wrong, and anarcho-capitalism can not magically protect you from evil people, but any other system ensures that you will lose to them. In USA you have two choices, you can be robbed by people who want to expand the state to insane degrees to the point they force you to buy healthcare "for your own good" and want to "help rehabilitate people" from drugs while funding the shitty near-brain-dead social science and prison industrial complex, or you can be robbed to a lesser degree by people who want to force you to follow the bizarre and completely illogical moral standards that were created two thousand years ago and largely based on a fairytale obviously no more real than any of the Greek or Roman or other myths from ages past. Most of Europe and almost all of the rest of the world are no better in their selections. Enjoy you Statist systems.