Audible breaks Apple's rules and adds mobile store link to iOS app

Mistake or blatant rule-breaking?

Remember when Amazon had to remove the link to it's store from the Kindle iOS app in order to conform to Apple's rules? Well, Audible, which is itself owned by Amazon, has added a link to its mobile store to the latest update of its iOS app.

Here's what the updated app looks like:

It's pretty easy to spot! I find it had to believe that Apple missed this when checking out the update. As far as I'm aware, Apple has not relaxed its rules, so this is either a mistake, or Audible is blatantly breaking the rules.

I've played with this link to the store and it does exactly what the link to the Amazon store did in the Kindle app ... takes you to the online store and allows you to buy audiobooks using either Audible credits or credit card.

According to the 'What's new' entry for the update on iTunes US, this update adds 'data storage optimizations for iOS5,' while over on iTunes UK three different features are highlighted - sort by length feature, support for iCloud and bug fixes and stability improvements. The screenshots on iTunes US (but oddly not on UK iTunes) even show the link to the store:

I wonder if this link will still be there in the next update.