SL6087 - Is there a way to turn off transmission only?

I’m looking at using the SL6087 for a product that is air-freightable. I would like to turn off ALL radio emissions whilst still being able to detect cell data.

I gather that the +WREGC command prevents registration with the networks and places the unit in “Spy Mode” but does it do more than just stop the registration cycle? Does is disable all radio frequency transmissions whilst keeping the receiver powered?

If +WREGC is not the way to go then is it possible to turn off the transmitter but still keep the receiver powered or am I just left with the option of powering off the whole unit?

AT+WREGC=1 places the unit into an airplane mode, it disables the RF transmition by the device and will prevent it from registering with a network on power-up (the value is stored and reread on power-up). It does not cause an IMSI disconnect other than through network timeout.
Similarly AT+CFUN=4 disables all RF (transmition and reception) and causes an IMSI disconnect.

So does that mean that it is still listening to network transmissions?