I wish. With the prevalence of using SMS for 2FA, short codes are very much in use. When you've got a provider that doesn't work with most short codes, you run into a frighteningly large number of difficult situations. Some providers will give you a "I didn't receive the text, call me" option. Some (grr...Venmo) don't. But it's one of those features you don't realize how often it's used until it doesn't work for you.
What country are you in?
The way I have seen them configured is they work from off-net if you prefix with correct codes.
Remember the foreign switch,smsc or ussd gateway is going to route the message if it has the correct prefix. The Routing (b number analysis) is looking up a prefix, to send it off.
It is up to your home operator to correctly handle this.
Source: 10+ years working with mobile operators
Source: used to work with SMS gateways for a living.
That said, short codes are rapidly becoming obsolete since data has become ubiquitous and everything is online now. The only one I ever use is voicemail.