The red flag emoji is a popular way to refer to "red flags" in relationships or potential relationships, which are signs that someone or something may not be trustworthy or safe. People use the red flag emoji on social media and in texts to highlight a particular behavior or trait that they find off-putting or disturbing. To use the red flag emoji in a joking way, people make a statement about a trivial behavior or preference and label it as a "red flag" using the emoji. People also use the red flag emoji to signal that a situation doesnt feel right, as a way to say "yikes" and send a warning. The red flag emoji meme has been used before, but it has exploded in popularity in the past couple of weeks. The trend has spread to companies brand accounts as well, including Dr. Pepper pointing out that places that dont have their popular soda are a "red flag" for them.