[eitland]

For Android, this is how I would approach it if I had to do it starting now:

Add a checkbox to show apps tjat aren't approved yet.

Make it default off. Turn it off every time you leave the Play store app.

Disable it for people under 18.

If a user still wants to install the app point out the app isn't approved yet and ask for password.

There, problem solved..?

[jjwhitaker]

It'll got the same route as grandma installing malware. It doesn't matter if credentials are needed unless it creates a real barrier.