Wearing a safety-pin symbolizes solidarity. By wearing a safety-pin you send the message you will protect those who are vulnerable to any kind of harassment. This trend, which began after the UK Brexit, sees the day of light in the USA following the recent results of the Presidential Election of 2016. 

I began wearing a safety pin to show that I do not tolerate any kind of harassment of a person because of their skin color, religion, sexuality, gender, disability, or anything else that might have a person be subject to some type of oppression.