[cheetos]

Is this unethical if everything is done locally and no data is stored or resold?

[kbart]

"Is this unethical if everything is done locally and no data is stored or resold?"

If it is hidden (no clear warning) and there's no way to opt-out, then yes, it is unethical imho.

[rubatuga]

Nothing unethical, just the fact that it is hidden may cause some outrage.

[sixothree]

Then what would be the purpose of collecting that data in the first place?

[bigbugbag]

Yes. It is unethical regardless of how it is done.