I ended up getting one from their website, pouchsafety.com, and I like it so far. It's obviously not a 100% solution and you still need to be a responsible parent, but it does a good job of adding additional piece of mind.
Harness and leash? They're not animals. This Pouch Device seems perfect. My kids can play around freely and I won't get stressed out trying to spot them at the playground. I'm gonna give it a try.
Has anyone tried the child tracking device from Pouch Safety (pouchsafety.com)? Looks pretty good. It's a bracelet that pairs with your iPhone/Android and alerts you when your child wanders too far off.