At this point, Apple is just milking all the free publicity to spread iPhone 4 awareness. Making phone calls is arguably not the primary use of these devices anymore and there's plenty of (artificial) grey area when one starts to argue about attenuation issue that it's fairly easily ignored when a potential consumer is about to buy into the iPhone/iOS platform anyway.

The free bumper + full refund policy seals the deal, until they release the new and improved iPhone 4 by the end of September.