> This sort of belief (that corporations do extensive testing and tuning of language) seems quite widely held, but I've never seen much support for it.
I recall integrating with a beta AWS A/B testing sdk back in ~2015 (may be off on the year) and I'm certain that some the examples in the docs were along the lines of, say, testing two different wordings for a label in your app and measuring the change in engagement. But that's not inherently nefarious, it's just analytics. They ended up shutting down that SDK and the web dashboarding for it IIRC.
Now, A/B testing for the purpose of tuning languages towards deceptive dark patterns? It's harder to prove, but I think it follows that if they're A/B testing other changes, there's no reason that deceptive changes wouldn't also be A/B tested as a matter of course.