This is exactly what had happened in the example I
was just demoing for you.
It said unauthorized on the phone.
It's saying, do you want to allow the RSA key fingerprint?
I selected Always allow from this computer
and selected Next.
All of these steps that I've just taken
are not going to harm your device.
So if you have your personal Android
and you want to give this a try, you
are not going to hurt anything by doing this.
You're just communicating in a friendly way to your device.
The only way you're going to hurt is if you type adb push.
Just don't take those words, and everything will be fine.