My point is that property laws apply equally to cash and to (so called) blockchain assets (and to many other types of assets): if you are within the court's jurisdiction, it can always compel you to give them whatever asset you supposedly stole from someone. If the thief somehow makes that impossible (e.g. hid the money, or hid the key that controls your blockchain assets), then the judge will make the thief's ass rot in jail.

If you are not within the court's jurisdiction, then it is powerless, yes. But that applies equally to cash, blockchain assets or any asset, really.

> The issue isn't that blockchains lack an automated enforcement of property rights, but that property rights are not enforceable at all (either by an automated system or by courts of justice). Why? Because in order to enforce property rights it is necessary that some authority have the power to seize assets from one person and hand them to another person. Blockchains are designed specifically to prevent that.

Blockchains are not designed specifically for that, it's just part of the feature set (if they are decentralized): things cannot be arbitrarily seized. It's a feature, not a bug. The court can seize the assets, but they have to get to the person that has the assets in their posession (through a key), just like for any other asset (i.e. they have to find the asset/key first, or the person that knows where the asset is).

Also, note that blockchains can't prevent a court from jailing you until you "cough up" the assets you stole, if you are within the court's jurisdiction, just like it works for any other asset.

> Cash doesn't have this problem, because it's a physical object and physical objects can be seized.

Yes, and physical objects can also be hidden. How do you seize the thief's loot, then, if it's hidden? Well.. you put him in jail until he coughs up where he hid the loot. Same with crypto assets: "until you cough up the key, you'll be in jail, and your own assets will be liquidated to cover your theft". Simple. How does a blockchain prevent that?

> You seem to be making the point that because sometimes cash is stolen and courts aren't unable to recover it this means that somehow property rights don't apply to cash?

You seem to be making the point that, because sometimes it might be difficult for a court to recover "crypto assets" from a thief, somehow property rights stop existing and don't apply to such assets, and courts become powerless (because "blockchain magic sprinkles"?). Many "crypto people" would like that to be true, but it really isn't.

Blockchains may complicate the work of courts and law enforcement (the same way that the use of cash in drug transactions complicates the work of courts and law enforcement), but that's not the same as saying that "property rights/laws" don't apply to "blockchain assets" (or cash).

EDIT: And, furthermore, because the fact that "blockchain transactions" are permanently recorded and readily available, unlike "cash transactions", it might even be easier to prove the theft in court. How would you prove to a court that the money that is in someone's posession has been pickpocketed from you? Seems more complicated to me, when there probably isn't going to be any register of it (assuming there's no CCTV around).

EDIT2: Also, note that some blockchain assets can be (and have been) centrally and arbitrarily seized by (e.g.) US courts, if they want, as long as the entity that controls the token is within US jurisdiction. Here's an example of Coinbase/Centre, which is within US jurisdiction, blacklisting (i.e. seizing, effectively) 100 000 USDC (i.e. ~100 000 USD) from a thief/hacker, due to a court order or some collaboration with law enforcement: https://cryptobriefing.com/100000-usdc-blacklisted-highlight...