[ntumlin]

Even if it does prompt, 99% of users will read it as:

Attention: You must click OK to play this game.

[mikestew]

I understand this, but that wasn’t my question. And the only comment in all this typing under my original comment that even made an attempt to answer my question of whether or not a piece of software can install a root CA without my knowledge, well, that got downvoted, too.

[user5994461]

To reply to your question. It's possible to install a CA without one's knowledge.

The battle update this week requested to run with admin rights, like a million of setup software. It didn't ask specifically "Allow setup.exe to install a system CA? Yes/No".

[mikestew]

Ah, thank you. And it’s the answer I suspected (use the admin rights of the installer), but apparently need to burn some points to get a confirmation.