I understand your point.

The short answer is that, indeed, it comes down to trust, and I really understand and respect your perspective.

The long answer is that it's very unlikely this trust would be broken. Let me explain:

Firstly, the accessibility service doesn’t provide anything close to "full control." It’s just an API provided by Android that gives accessibility events, like changes in the screen layout and the UI nodes present on the screen to infer the type of content shown (Reels in my case). You can check online for details on accessibility events. It's nothing like a constant screen recording where the app gets all your data.

Also, Google is very strict with these permissions. When you publish an app on the Play Store, you need to clearly disclose why you're using those permissions. If you do something wrong or try to abuse this, they will take your app down. Anyone who values their reputation wouldn’t attempt something like this just to sell some user data.

Lastly, ScrollGuard doesn’t need to connect to any server to work!, all the detection happens on the device. So, if you want to be extra cautious, you can always go to your phone settings and block internet access to ScrollGuard. It will still work, and without internet access is imposible to export any data.

If you want even more control and just need a solution for Instagram, you can modify the app yourself. I wrote an article a couple of years ago on how to do this here: https://breakthescroll.com/block-reels-instagram/