The play tests run against production, and a test account waiting in the
public chess queue was seated across a real player (karimelshafei22), who
then played an account that vanished with the test's teardown. Nothing in
any queue knew a test account from a person.

profiles.is_test (migrations/2026-10-27-test-accounts.sql, applied) marks
an account the tests made. It is a column, not a name: usernames and
display names are the player's own choice, so a name marker could drop a
real player into the test pool. The profiles guard keeps the column out of
a player's token, both ways. The migration also marks the 23 ZZZ-* test
accounts earlier runs left behind.

includes/match-pool.php keeps every search to the searcher's pool: the
queue call and the status pickup of an earlier queuer in chess, ludo,
domino and backgammon, and domino's public tables of three and four.
Unknown means no: a profile that cannot be read is seated with nobody. The
bot fill only ever holds the player's own row, after that search, so it
needs no change. Real players among themselves pair exactly as before.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>