Disabling signature verification is equivalent to removing the lock from your front door and leaving a note that says “everyone welcome.”
When you modify an APK—by changing a color, removing an ad, or cracking a license check—you inevitably break the original signature. If you try to install this modified app on a stock Android device, the Package Manager will instantly reject it. The error message, "App not installed. The package appears to be corrupt," is actually Android saying: "Signature verification failed." lucky patcher signature verification killer
This is the greyest of grey areas.