On a mesh that predates the record, every handover has to begin by writing down who
already holds the seat — otherwise the next holder cannot be assigned beside it,
because two eligible claimants with nothing on record are refused. Found on the
live mesh minutes after 0040 moved the bus seat's row: the standing holder no
longer satisfies what the seat delivers, on purpose, and so could not be recorded,
and so nothing could stand beside it.
Recording who already holds is not making a new holder. Derivation never read
what the seat delivers, so the standing holder holds regardless; when nothing is
on record and the named assignment claims the seat at its scope, only that claim
is checked. Every change of holder is still judged in full.