So anyone can use the web browser on their iOS device to view nude photos on the 500px website, but they can't download the app and view them via that? It's a bit ridiculous really. Are they going to start blocking websites they dont approve of as well?
The point is, if I have set my son's iOS device to block Safari as well as apps rated as mature, then he won't be able to do either.
If 500px's app was rated 12+ because it's default was 'Safe On" (according to one of 500px's owners: http://news.ycombinator.com/item?id=5099607), and my son can just toggle a "Safe On" switch in the app, it side-steps my parental controls.
