This is an advantage of the android style permission system in this case, the 'Services that Cost you Money' section could reveal this dodgy behavior quite easily.
Apps with in-app purchases have a giant message on the App Store that, upon clicking, brings you to a list of things the application has for sale.
Not to mention there's a restriction on iOS devices that allow you to turn off in-app purchases all together.
It's like blaming Comcast because your child purchased expensive pay-per-view material when you could have easily blocked the channel.