Deregistration GSM network mandatory?

Hi,

After sending just an SMS, do I have to de-registrate with +COPS=2 before powering down the module?
I know it work perfectly whether I do it or not. What I would like to know if providers make a problem of it if you don’t.

I would like to do without as it cost energy.

Yes, you can cause problems by not shutting down properly - especially if you do it frequently.

The networks can notice it, and might start to “blacklist” the device as faulty…