Also, by changing course you find out their intent.
For example, we change course, and they do too. The American captain would immediately notify the fleet and our planes would be on alert.
One thing Trump probably has told them, is we will not let these people apprehend us.
The USNS Invincible was traveling in formation with 3 warships of the Royal Navy. She may have been under the tactical command of the Brit Commodore. From what I have read, she is a missile tracking ship. Her tracking radars belong to the U.S. Air force. Her operational mission may be under the control of the AF.