What is the route?

The US ditched this silly policy for domestic fligths back in 2003 when it implemented 100% screening of checked luggage. Anecdotally, it is also spottily enforced xUS by domestic carriers.

As a practical matter, you should plan on your bag being checked and transported to your ticketed destination. At a minimum, if the bag is pulled, you will need to deal with the carrier to get it back and have your ticket refared.