I think it's actually the SafetyNet Attestation API. Checking for root means requiring "certified, genuine device that passes CTS". It also excludes "genuine but uncertified device, such as when the manufacturer doesn't apply for certification". https://developer.android.com/training/safetynet/attestation...

I was reluctant to unroot an old phone to try Android Pay, but having to do it just to watch some movies a tad too far. For me anyway. https://phunehehe.net/xperia-android/