> Is really any guarantee that they even follow those?

No, there isn't. I just don't understand how naive (or imbecile) people are. The most valuable thing for these companies is people's data used for training, so giving unrestricted access to a tool from them and believing they will never take advantage of it to gobble up whatever they want from your computer, just because they told you they'll never do that, swearsies, is naive, or incredibly stupid.

Insulate yourself, or better yet, go local whenever possible, and there isn't much you can't do local if you have enough patience.