Asking about policy here is a succinct waste of your time. You'll only get the opinions of other devs here. Apple won't respond.
Apple Developer Forums is a community for discussing developer-level issues with Apple’s SDKs and tools. It is not an official Apple support channel, even for developer issues, and it’s definitely not the right place to feedback/get answers about policy.
No one here can promise what app review will/won't reject/approve.
>That suggests a business oppourtunity to me.
My opinion is that it sounds more like a no-fly zone, and it would be naive to think you've found a topic/type of app just waiting for you to provide, that everyone else has simply overlooked.
Good luck.