Even if your device is not ‘discoverable’ for Bluetooth? Or does ‘discoverable’ only mean your device is open for pairing?
No, you have to have bluetooth on - which the hospital app that you’ve purposely downloaded will do - to be “seen” by the BLE markers to help you with finding your way around the complex.
Again, for grocery stores, it’s just a proximity sensor that “sees” someone cross a beam/reflection of the IR that triggers the freezer section lights to come on, and/or an ad to be played because you’re near that product.