Okay, then what? The addicts aren't going to have an epiphany and stop being addicts. Where do they go next?
No, they are not. My solution was for Starbucks, and it is a far better solution than putting people out of jobs.
Easy: public parks. Libraries. Blighted neughborhoods, even ones right up next to decent neighborhoods. Because we tried all of that already. We have tried cracking skulls and sweeping them under the rug. Didn't work. Hell, there are so many of them at this point, that they are in the bathrooms only because of space overflow happening already. Do you think any of them somehow LIKE shooting up in a Starbucks bathroom? I think we can at least agree that they would rather be somewhere safer, more private, etc.
So, then what?
It is a legitimate problem, and maybe should have its own thread. But, I'll discuss it here to avoid you believing that your questions are unanswerable.
My solution is simple, but not completely libertarian. I admit that it does not follow the pure libertarian ideal. It amounts to secure homeless shelters, open to anyone and designed to be lived in by people who are likely to tear stuff up and make messes. So, we're talking cinder block walls, metal doors, toilet/sink combos and poured concrete furniture. Just a basic row of rooms, like at a motel, but you walk in, shut the door behind you and do whatever you would do in a Starbucks restroom.
The rules: One person to a room that can be locked from the inside. No searches for drugs, or any other contraband. No police presence. Security, cleaning, and feeding provided by you - Fort Fun Indiana - and others that you recruit from among your fellow altruists. You could pioneer this, by starting a gofundme, or whatever is the new gofundme. That's libertarian.
Homeless caught camping anywhere else will be given a choice to go to the shelter or go to rehab in custody. That's the part that ain't libertarian. I look at it this way: Libertarianism is for adults. I don't advocate smoking, drugs, gambling, and sexual freedom for kids, but I do for adults. Libertarianism is not for the mentally ill, for the same reason it is not for kids.
If a place like that is available, it would be insane to want to live in the park. Get such insane people treatment, whether they realize that they need it or not.