LTE & Lora/Sigfox Antennas

[Alexandre Goncalves]

I read in the documentation that you must attach the antennas when using LTE, Lora and Sigfox.
The questions are:

1. Is it realy safe to turn the board on without the antennas when using only the Wifi or BLE radio?
2. When does the LTE or Lora/Sigfox antennas are really necessary? When are the radios tuned on and off? Is there a command for that?

Thanks in advance.