I'm developing a children's learning app for preschoolers where the basic idea is that the parent hands the device to the child, and is free to then leave the room. I anticipate, of course, that the app will run as expected; however, on the off-chance something does go wrong, it will most likely affect the child's ability to learn and progress. Thus, in such an event, I may need to notify the parent as soon as possible. Some ways I have thought of to accomplish this are: 1) Have my app say "Uh-oh" or some other sound over the speakers 2) Send the parent an e-mail using the address listed in the corresponding Address Book entry. In both cases, I would also show a message telling the parent what happened and how to fix it.
It sounds like you might have some good ideas for getting the parents' attention (though unbidden loud sounds might be a little shocking). However it seems more than likely that the parent will not get an email immediately, nor will they be in the same room to hear the sound.
Perhaps a very friendly, kid-centric message in a banner or modal (depending on how drastic the situation is) that tells the child that something went wrong and asks the child to go get their parent will be a good addition to your ideas.