So flaw in that is this, IP address is kinda easy to get if the person belonging to it doesn't use a VPN or know how to set up a dynamic IP with their ISP. Having ages listed for the world to see allows someone to see that a person lives at that IP address with that age and can be traced to a physical address. Hell it wouldn't even be a stretch to say predators could use that to their advantage to find new victims regardless of what they plan to do.