Privacy stance on defeating hidden ownership

[Erilla]

Question

Raider.IO lets a player hide the link between their characters, and SlashWho's MVP treats a privacy-hidden owner as a legitimate, respected outcome — a partial result, never an error. The achievement fingerprint deliberately defeats exactly that: it reconstructs the link from data the player did not choose to publish, and four of five characters the bot tested had the owner hidden.

Where does SlashWho stand? Decide the position and what follows from it: what the public /privacy page must say; whether suppression as it exists today is sufficient; whether a self-service opt-out has to precede this shipping; whether hidden-owner characters are excluded from fingerprint discovery entirely, included, or included only under some condition.

This is the decision that can reshape or end the effort, and three other tickets hang off it.

[Erilla]

Unblocked: #16 resolved.

Two independent research tickets converge on the same cohort, which narrows this decision considerably. Blizzard's terms hinge on "invasive of the privacy of another person"; UK GDPR Art 6(1)(f) fails both its balancing and necessity tests — and in both cases the failure is specific to players who deliberately hid the link, because a hidden-owner flag is documented evidence of a contrary expectation under Recital 47. For everyone else, the case is tractable.

So the question to decide here is not whether SlashWho should do fingerprint discovery at all, but whether it can do it while excluding the people who signalled they do not want it — a signal #16 notes is detectable — and whether what remains is still worth building.

The other mitigation that materially moves the risk is keeping such pages out of search indexes.

[Erilla]

Resolution

SlashWho will treat Raider.IO as the sole privacy signal for achievement-fingerprint discovery.

• A character whose Raider.IO ownership is privacy-hidden is excluded from fingerprint-derived linkage; SlashWho will not reconstruct a relationship that Raider.IO marks as hidden.
• For publicly linked Raider.IO data, SlashWho follows that upstream visibility and will not add an independent suppression or self-service opt-out mechanism for fingerprint-derived links.
• The public /privacy page must state the first boundary plainly.

This preserves a viable fingerprint feature while respecting the only explicit, machine-readable privacy preference available to SlashWho.

[Erilla]

Reversed

This resolution no longer describes the system. The maintainer removed the privacy-hidden exclusion after implementation (#33).

The reason is that the exclusion was not implementable as decided. The only signal available is Raider.IO's characterDetails.user being absent (ownerId === null), and that state covers two unrelated populations:

• a player who withheld the ownership link — the cohort this decision meant to protect;
• a character never claimed on Raider.IO at all, which sampling suggests is the ordinary case.

The code could not distinguish them, so it excluded both — including the bank and levelling alts the fingerprint exists to find. Rather than narrow the signal, the maintainer removed the gate on both the sweep root and its candidates.

What this gives up, stated plainly: a fingerprint-derived link may now connect characters whose Raider.IO ownership is not public. That drops the first of the two mitigations #16 identified as materially moving the UK GDPR balancing and necessity tests. The second — keeping such pages out of search indexes — is unaffected by this change. Manual removal requests are the only remaining exclusion route, and /privacy now says so instead of promising the exclusion.