a whisper network is most commonly when (usually) women inform each other about men who are sexual predators, (usually) in workplaces.

Oh, that makes sense then. I’ve only ever heard the term within the trans community, and most of the trans people I know (myself included) are t4t and gay. I don’t know what the cishet people are up to. In the trans community, whisper networks are for well-connected abusers to DARVO their less popular victims. The victim has no opportunity to respond to the accusations and may not even know about them until all their friends have cut contact.

And that’s one of the issues cited by Norway’s data protection authority with Shinigami Eyes:

It is Datatilsynet’s view that to be marked through Shinigami Eyes may entail negative consequences for the data subject, regardless of whether they are marked as being pro- or anti-trans. Being marked as anti-trans could cause one to lose their job, or friendships, and the individual could be the target of hate and mistreatment. Being pro-trans could, in certain communities (for example religious or very conservative communities), be construed as negative as well, similar reactions as described above could be imposed on the data subject. The negative impact must be viewed as particularly intensive, in light of the individualised nature of the marking, in addition to the data subject not having information about the marking nor understanding why they received such a marking. It is therefore also in particular difficult for the data subject to present an opposing view. This could also entail fear, irritation and other broader emotional impacts, which, according to the WP29, must be taken into account in this balancing act.

[…]

In addition, it must be taken into account that since the processing is occurring without the appropriate information being provided to the data subjects, the data subject is prevented from exercising their right to object in accordance with GDPR Article 21. The lack of adequate information being provided to the data subject will be further examined below in its own section.

Personally, I agree with this legal decision. The final verdict from the data protection authority is that the legitimate interest of trans people to be warned of transphobia by an app, which is easier than using their own judgement, does not outweigh subjects’ right to safety from profiling and their right to object. Who decides whether a user’s submission is added to the bloom filter? A machine learning heuristic and an unknown, unidentified group of people who the Norwegian government was unable to track down. There is no accountability.