Emergency Calls Only?

Since I bought my smartphone it has done this many times now where I want to make a call and I can't because it says, "Emergency Calls only". Now, as a computer programmer by training years ago and from understanding what this would be for, it is mainly when there aren't enough cell lines during an emergency and they are telling everyone, "You cannot make a call unless you are calling 911". However, there cannot be this many times when this is happening. So, I know it has to be something else. So, thinking creatively about it I realized it likely is about software since most people don't want to take time to install software updates. So, this is a way to force people to update and to greatly inconvenience them by Forcing them to shut down their smartphones so they have to start them back up (takes about 5 minutes or more) that you cannot make any calls or text. So, after stealing this time from anyone who doesn't want to be doing this, the operating system resets itself. On the other hand this also could be an indication that your cellphone has been hacked by someone too. So, this is something to think about regarding the words (Emergency calls only) when it comes up on your phone. At the very least it means "YOU CANNOT MAKE A PHONE CALL EXCEPT TO 911 AND SOMETIMES NOT EVEN THEN."