At least for BLE one could use advertising packets to transmit the data, sensor beacons tend to do this with e.g. a temperature. There is also the scan-respons

At least for BLE one could use advertising packets to transmit the data, sensor beacons tend to do this with e.g. a temperature. There is also the scan-response mode, initiated by the device scanning for others. And you can use plain GATT without any authentication, but that would be fully unencrypted iirc. Rangewise it might be possible to reach 100m in an open field under very good conditions, especially when utilizing coded PHY, but not with default power levels I think. There is a lot more to know, one place to start is 'Intro to Bluetooth low energy' by Mohammed Afaneh