It would be nice to have an option to register a number that is the only valid to send the smscon commands.
I know the chances are pretty low that someone else will actually send a command to my n900, but they still exist. And i wouldn't be overly happy to expose my current location or a picture of myself/surrounding to someone that is pinging my phone.

Or did i somehow miss the point and my n900 only returns requests to a certain predefined number? Meaning that anybody (like 12345) can send a command, but the reply always goes to my defined number (i.e. 7890)...