Give every identity a vault it must keep live: a working set grown from its own past answers by a memory-hard function, so the state cannot sit cold and be recomputed on demand. Each epoch's answer posts a checkpoint, and a jury may demand one random mid-range re-derivation - without the RAM held, a copy stalls or fails. A new identity starts its voyage at checkpoint zero, so weight accrues only from epochs genuinely held. One plume of the vault id inside every answer makes copies visible when two accounts post the same state. Clones cost resident RAM per head, non-poolable, plus the wait.