We're the first to admit that it's going to take some time to get the balance right. Fundamentally though, we're pretty committed to the idea of making this useful for both parents and for children, and hoping that "last defenses" won't be needed.
As an example here, we built the system intentionally such that children would know their parents' location in addition to the parents knowing the child's. That's got a few implications that are pretty important, but for starters it means that parents aren't asking their children to do something that they're not willing to do themselves -- that actually raises the bar pretty significantly, and I think it does drive home to the parents exactly what it is that they're asking of their kids.
Do we think that parents should know when their kids have disabled the app? Right now: yes, we do. I'm open to the idea that we might be wrong on that, but to my mind it's just an extension of the negotiations about trust and so forth that parents and kids already need to engage in: if you want time when your parents won't be tracking you, you negotiate to get that time. It's like the negotiation that happens whenever a child wants to do anything without parental, or adult supervision. To my mind privacy invasion and responsible parenting are different things, and I think the straw-man arguments presented in that direction are a little unfair to parents, though I concede that there will always be exceptions.
We did actually look at doing this for spouses -- not to detect cheating (a cheating spouse will be even more motivated to subvert the system than a child), but to help out with stuff like "are you near the supermarket? Can you pick up some milk?", but fundamentally people don't seem all that interested in it. I think employees would be kinda similar: you get fired if you're not getting your work done, water cooler or no.