How do you know if someone you see is in a relationship or not?

So I made an app with this in mind. Basically, if someone is in your immediate vicinity, you can see a digital profile of them. Currently, it has 3 fields, hobby, what they are considering buying, and single or not. I am trying to gather feedback before starting a big marketing campaign. If that sounds interesting, please let me know what you think. The App (ÒÓTD) is available on the App Store