If we could create an app that when you open it, the app will check for other users within 6ft of your phone. If this 6ft distance is crossed it will cause both phones to vibrate, indicating that you need to remain at a safe social distance. You could open the app and it would run in the background (similar to how you still get emails even though you aren't in the mail app). Giving people a reminder would allow more people to stay safe. I can see this idea really take off when people start returning to businesses. If a whole company decides to tell their employees to download this app it would create a safer work environment.