I don't know man. I heard about this app being deployed in Singapore a while back but their govt appears a bit more draconian.
I'm a tin foil hat guy, so if it gets adopted, I'll have to start carrying a spare phone in case it had the ability to identify users within the proximity without having blue tooth on. I'll carry a Nokia 208 feature phone around and just make sure I know where I'm going within having the phone on me. Same as punting...
I think the app is relatively safe. You're right about Google maps. I feel it will know where you have been but also stores this data on your phone. Not a fan, as this info can be readily accessible compared to a cloud environment where will require authentication.
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