As I mentioned in my post about App Update Pricing yesterday:
I get it that there could be a totally different way of dealing with all of this, but for now this is the only way developers can earn money for what they're doing.
Stephen Hackett sums it up nicely on 512 Pixels, finishing with a great paragraph:
The bottom line is this: developers should be able to work on their product in a sustainable way. Realmac are some of the good guys, and to have to backtrack on a business decision is a damn shame, especially in a world where people pour money into IAP-based games day and night.