Why would you want them to disappear? I have Flurry installed in my apps to help me identify usage patterns, and see which types of people use my apps. I don't think there's anything wrong with that.
Shouldn't make much of a difference. It's more useful for services tracking users across several apps and building profiles without their knowledge (eg. most ad networks).
Yet, there are other ways of implementing this, from "nice" things like UIPasteboard coordination to "nasty" things like hiding data in AddressBook: it doesn't really affect these developers at all.
