Gotcha, though in either case, it's the same client
that {retracts|edits}
the message as has sent it (and presumably chosen the id), so if it cannot
figure out a sensible strategy for generating ids, it presumably can't
Precisely. When validating sender, the risk of id clashes stops beieg an
issue since the sender knows they need unique IDs for corrections. So using
message@id instead of origin-id or stanza-id is the way as in the correction
XEP.