I have no idea about an app but I wanted to say that there is absolutely nothing wrong with keep tabs on your kids. Even if they aren't known to get into trouble. As a matter of fact I'm pretty certain people would be quick to judge if they asked where your kids were and you had to reply with 'I don't know.'
Would I have hated something like this as a kid? Certainly. When my two and a half year older daughter gets older will I be keeping tabs on her? Certainly. It is responsible parenting to know where your kids are, who they are with and what they are doing. I grew up raised by a single grandmother that was unable to keep track of me. I hung with the wrong people doing bad things in places I really had no business being at. I dropped out of school, went to jail several times and ended up in rehab. This all over a decade ago and thankfully long in my past and my life has changed including going back to school. Now I'm not saying it was my grandmothers fault that I got into the stuff I did. It was my fault. But if I hadn't been living the lifestyle I had a child and young man I doubt things would have turned out like they did for me. Thankfully things can change if you want them to.
Just look at the things children can be exposed to in music, TV and various media. Glamorization of drugs, teen pregnancy, violence, etc.. Like I said, a responsible parent does what they can to minimize this stuff if they can't outright prevent it. Most of the people who are quick to criticize most likely do not have kids of their own.
To much personal information probably but I hope it gets a point across and I'm not trying to say this will happen to all kids but the potential is out there.