When my wife and I first started dating, we both lived in D.C. and she had a business trip to San Francisco. She had never flown first class. I rang up United and had her flight home upgraded.

• She thought it was a little bit weird that I could call up an airline, without her confirmation number even, and just alter her trip.

• But I did this to put her in first class.

We’re still together 23 years later because she decided that it was more cool than creepy, but I also suspect most people don’t realize how little security there is around airline reservations. If you know a passenger’s name and where they’re traveling from and to, it’s not hard to get their full travel details and even change their trip (even without knowing which flight exactly they’re on to begin with). And that’s a power that isn’t always used for good (like upgrading someone that you’re seeing).

Perhaps a decade ago, a reader of One Mile at a Time cancelled an upcoming international premium cabin flight reservation that site author Lucky had booked, and had rebooked him on a domestic trip instead. The itinerary fortunately was able to get reinstated! But it was a good reminder not to mention details of upcoming travels – to always write about the past.

This isn’t usually a problem because of the most important protection of all: security by obscurity. For most people, nobody cares enough to try to hack you – or to mess with your reservations.

But what if you call Delta customer service and the agent on the other end of the line is your ex? And she learns that you’re now married with a baby?

Received a callback from Delta [customer service], and immediately the voice on the other end was familiar. As we started talking, she confirmed some details about me and my trip and then in a sarcastic voice, “Wow, first class with the wife and baby, huh? Pretty fancy.”

We didn’t have a long catch up or anything. She sounded slightly jealous. We had a slightly terse, “Oh wow, I didn’t expect it to be you” kind of moment once we realized who the other was. She said she couldn’t help me with my issue and I quickly ended the conversation. Wife beside me was confused.

The passenger didn’t even give his ex a 5-star rating in the follow-on survey after the call, he says, because “she didn’t resolve my issue!”

I have to think that Delta has a policy that reservations agents can’t work on issues for people they know personally. The ex should have transferred him to another agent once she discovered who it was.

For years, frequent flyers have been calling an airline’s English-language foreign call centers to get around long hold times. That doesn’t work with Delta anymore, since they now just route those into their main queue. I still do it with American. But another thing that it gets you, it seems, is reduced likelihood that the call will be answered by your ex.