That's opt-out, though? It's nice that they tell you, but they don't give you a choice. They're just warning you that you need to opt out. That's not the same as opting in.

They're also claiming to log anonymous data while the data they collect is actually pseudonymous as its tied to your specific machine/user, which means it has a whole different status in different privacy jurisdictions. It seems like they could make the data collection anonymous relativelt easily if they just stop tracking individual user installs, though.

> They don’t collect data until after you’ve been given the chance to opt out.

That does still make it opt-out, though, even if it's a friendly opt-out. Microsoft's dotnet tools do the same thing.

> Doing that would skew the reports to more active users & automated scripts. If you’re asking questions like “how many people will notice if we deprecate this?” you don’t want to count the guy who hammers “brew update” every other command many times more than someone who updates weekly.

I know why they're collecting personal identifiers and I completely understand their reasoning behind it. Every website and service does this in some fashion because most requests are automated. You should still ask before you submit any telemetry, though.