The idea that someone would be bothered because someone else called their app "Quiet" really bothers me: if you want a name that you own, you need to come up with something reasonably unique (I mean, even "App Store" passes this test in ways that "Quiet" fundamentally doesn't) and then start asserting trademark rights on it.
I agree. Using a common dictionary word as the name of your app is going to have this problem. Look at the mobile App Store and you'll see many apps with the same name (with different punctuation at the end).
These guys didn't stumble upon to something new, it's been there since the early days of the iOS App Store.