At some point dating stopped having warning signs and started having flags. Red ones, obviously. Then green ones, for balance. Then beige ones, for the crime of being boring. There are now enough flag colors to run a small navy, and people deploy them with the confidence of air traffic controllers.
Why the metaphor caught on
The flag works because it turns a fuzzy feeling into a verdict. Something about a person is off, but naming why is hard and sounds harsh. Calling it a red flag skips all of that. It is a ruling with no explanation required, which is exactly what people want when they are recapping a date to a friend. The flag does the judging so you do not have to.
The beige flag was the tell
The moment the beige flag appeared, the whole thing stopped being about safety and started being about entertainment. A red flag warns you. A beige flag just mocks a mild personality trait, the same three restaurants, the too-curated playlist, the profile that lists a height and nothing else. That is not a warning system anymore. That is a genre of comedy.
Everyone is someone's flag
The uncomfortable part, and the part people avoid, is that the flags are not one-directional. You have been someone's red flag. You have absolutely been someone's beige one. The whole vocabulary is designed to be pointed outward, at exes and situationships and that guy from the app. It works a lot less comfortably when you turn it around.
Which is the more interesting quiz
That is precisely why the more interesting test is not which flags to look for, but which one you are. It is easy to catalog everyone else's warning signs. It is a genuinely funnier exercise to find out that the call is coming from inside the house, and to get a specific color for it.
Brainbuffering has a Red Flag Index that turns the lens around, plus a standards detector for the people doing the flagging. Both are on the home page. Bring your ego.