I've long been toying with the idea of an L2 for unenforceable ("trivial") amounts. The only mechanism here is that if the coordinator misbehaves, a user can prove it and send *all* the funds to a fallback. The default fallback is half-burn, half-fees*, but it could also be some custodian of last resort.

This is strictly weaker than, say, lightning, but I think it's the best you can do for tiny amounts: ensure that there's no profit in cheating.

The problem is that I don't think you can prove all the different ways the coordinator can screw you. It can fail to respond at all. It can claim to be unable to make any lightning payment you ask for. You can probably prove misbehaviour for any transfer to/from other internal users of the same system, but that's not very useful if you can't get funds out!

So I'm posting here in case it forms a useful component for building something. Good luck!

* Christian Decker nominated this a "Nero protocol", which I like.