What constraints and how do you enforce them?

I'm curious what positive externalities you're thinking about? Being able to make plans for the future?

A male in a country that is about to enter a war could decide to leave to avoid conscription, depending on the odds

Doesn't take a weatherman to tell which way the wind blows

Again, as I said, "aggregating public and private information through market mechanisms".

That's vague enough to be more or less meaningless, where specifically do you see positive externalities outweighing the numerous negative ones?

If that strikes you as vague, I strongly recommend you to read at least an LLM summary of "The Use of Knowledge in Society".

Just give an example, dude. Stop being abstract.

Ah yes, vague non-solutions.

They will be uttered in response to criticism and then quietly ignored until the inevitable. Rinse and repeat. A true mark of a grifter.