How is that different to a bucket shop? https://en.wikipedia.org/wiki/Bucket_shop_(stock_market)

It's not really. They're transparent, auditable, and typically they're designed to use over-collateralization to prevent liquidity problems, but they're not 100% immune to them and still count as bucket shops IMO.

But they're absolutely not fraud or "fake stocks".

According to the Wikipedia link, bucket shops are illegal gambling.

So if what this is doing isn't any different than a bucket shop... I think we'll see the same outcome.

Are they illegal everywhere though?

The spread betting companies in the UK work very much like bucket shops and are not only legal but tax free. Unlike these blockchain things they are regulated and unlikely to run off with your money.

Yes I think that's very likely. The closer DeFi gets to traditional markets the more likely enforcement is coming.

What are some possible enforcement mechanisms against Ethereum DeFi smart contracts?

I imagine very few people would be interested in smart contracts if it became a defacto legal standard in the US and Europe that these contracts are unenforceable.

Of course this doesn't address contracts being written out of Russia or traditional financial havens, but how valuable is a vehicle which can't be used to move assets into or within the US or Europe?

I think the question of enforcement is the wrong one.

Smart contracts are already unenforceable via the existing legal system. It's the blockchain that enforces them, and it will continue to do that regardless of their legal status.

The greater Ethereum community accepts to put restrictions into place, or the US/EU/China puts sanctions on Eth owners and traders. You get to either move to Sealand, or accept restrictions.

I'd love to see the DoD/CCP conduct a metadata drone strike agaisnt addresses that were generated for a specific transaction x seconds ago, correlated with some IP addr correlated with some location that ended up being a server running in supply closet on one of their military bases.

Esp for chain running evm compatible contracts that are more scalable than ethereum and can have millions of ephemeral validator nodes.