Excellent thinking! A few comments:
- You may want to link to my generalization of encumberments for smart contracts: A layer 2 computing model using optimistic state roots
- If this ends up being a common pattern, then it seems like it would make sense to start standardizing how user wallets can verify receiving encumbered payments so that basically everyone’s wallets can use it (unless the goal is for there to be specific highly-capitalized “sinks” that wait out the maturity mismatch eg. exchanges). But this may prove difficult if there are many flavors of plasma especially those that use more exotic cryptographic assumptions. It seems to me that the “ideal” general-purpose approach here is to provide a SNARK over a formal verifier proving that claim that if the user plays a game as specified by a provided piece of code using a specified block of data as input then the user will be able to get their coins out; but is there something simpler to implement than this?