It logs the timing as well, which could be sensitive data. For example if an employer were to gain access to this information and tie it to an account that someone thinks is anonymous, they'll know when you weren't working but getting paid to be at work. Or it could be used to determine when some is at home or out. Or be used as evidence for holding certain views.

It's unlikely for a single employer to get that data. But I wouldn't put it past the five eyes to set up an instance, mine data, and use analysts/AI to cross-reference it with other user metadata.

It's like J Sakai says in his security pamphlet. It's bad practice to give any information to feds, even 'benign' data because it helps them to build profiles on you and others. To offer a rather extreme example, if they know you were upvoting a comment at 16.07 EST, they can guess it wasn't you at a protest at the same time. This means they can narrow down the suspect list to the other handful of people with your build, etc, who go to protests. Being lax with data means the feds have an easier time undermining the efforts of people who are tight with their data.

It's a privacy issue that I hadn't considered. I knew our admins could see this data. I didn't realise it was visible to other instances.