Thanks, the vault picture is a clear way to put it. In PoA the bond and what it protects are not in the same unit, so a fixed bond gets weaker as the chain holds more value, and slashing alone doesn’t fix that.
The Interlay rule is the part I’ll take: limit what the chain accepts to what the total bond covers, with a safety margin, and only raise the limit when the bond grows. We’re still on public testnet with no token on chain, so this can go into the design before mainnet instead of being added later. I’ll write it up together with how authority keys are split, and share it here when it’s ready.
Thanks for the pointer to the Interlay docs, that’s the example I was missing.