While in reality the txout tree isn’t actually being enforced, every bit of code interacting with the tree and each party can be tested as though it is, and since NOP and CheckSig are allowed in standard scripts, the protocol can be tested on mainnet with real funds.
I call this kind of testing a cargo cult protocol lmao.
Overall pretty great analysis. I'll probably reference it pretty often. I'm pretty hyperfixated on multi-party channels right now and I did already know that vtxos would be a helpful extension, but this does clear up a few implementation specifics I didn't know about yet. So thanks for that.