If you’re a US citizen or national (such as a resident) and are traveling abroad, you can join STEP and get important information about what’s happening in your destination(s).
Let’s say there’s political instability, rioting, or some other kind of problem going on that can compromise your safety. You can find out quite quickly with this program at no cost.
From the STEP website:
Receive important information from the Embassy about safety conditions in your destination country, helping you make informed decisions about your travel plans.
Help the U.S. Embassy contact you in an emergency, whether natural disaster, civil unrest, or family emergency.
Help family and friends get in touch with you in an emergency.
Join the Smart Traveler Enrollment Program on the U.S. Department of State website — it’s easy and free!
By joining, they will help you if your passport is lost or stolen while you travel or if there is an emergency.
If you are very interested in your privacy, etc., just keep in mind that you did probably register to get on an airplane and declared your destination…
This is just pure speculation on my part here, but if they know where you are and something really bad is happening, they might be able to send some folks to come rescue you. If I remember correctly, they state somewhere on their website that they expressly won’t do this, but that may be a liability thing.