I don't think it's more deceptive than putting favorable reviews on the back of a book, or those any ads where they get actual customers to review a product. The app store is both a promotional channel and a marketplace.
Interesting point, however the main difference between a printed book and the app store is that the product on the app store can be constantly changing based on the user feedback. If reviews are inherently prejudiced in one direction, does that leave much incentive for developers to improve their app?
On the other hand, a private engagement directly with developers could prove to be more beneficial since it allows developers know of shortcomings/user-expectations without negatively affecting the overall ratings. This way, they can improve the app without having lingering negative comments affect the perception of their updates.
