This isn’t quite what I meant. I am referring to the force close fees. I know from experience that you can run a lightning node at a loss. If a mint operator doesn’t charge sufficient fees on lightning transactions, then a force close could cause them to run at a loss (because of on-chain force close fees), which would mean that the mints liabilities over time (ecash) could exceed total liquidity (on-chain + lightning channel) if the mint operator doesn’t provide some liquidity coverage. This is why public auditing may be important.