This isn't supposed to happen, but it does. I have had Apple ask me to remove apps (one of about ten), because of "marked similarity" with other apps in my store (I had a single codebase that was recompiled for various locations, and also rebranded, but the app was basically the same).

I saw one developer that had over 400 nearly identical apps. They were some kind of "local guide" app, and the only difference was the text content. Otherwise, even the branding was exactly the same, and each app was its own app; not a single app, with multiple faces.

Apple does not let you change your screenshots and app previews, after your app has been published.

That's because some game developers wrote crapplets, then replaced the crud screenshots, with ones from commercial apps.

Grifters can be damn clever, and learn to push the limits of any system.

And one of the reasons that the Apple App Store is such a rich target, is because it makes serious money. All other marketplaces pale in comparison.

There's a lot of people that want to "bring down" the App Store, so it's just as cruddy as the competitors. Not sure that would work out the way people think.