This is a form of marketing that is becoming more and more common. Apple has INTENTIONALLY worked with a firm that develops fragrances in order to give each new iPhone 4s the smell of... Apples! Some may disagree that this scent is similar to "apples", but nevertheless this was Apples intention.
Somehow they've engineered a way to periodically or by cause & effect (ie; installing/removing ear bud jack), release or "project" the smell from the device. This is why from time to time the scent appears stronger than at others.
We have 3 iPhone 4s devices in our household and the experience is congruent between all.
I personally love the scent, but I am somewhat concerned with the chemicals used to produce the fragrance.
There are MILLIONS of people with sensitvities to this sort of thing. So although this was "cool" or creative from a marketing standpoint, it was definitely INsensitive from a users standpoint.
***You who are reading this... YOU have greatness in you. At any moment you can decide to step INTO your greatness and reveal what you have to offer to the entire WORLD. What we need now more than ever is for people like YOU to REFUSE to die without leaving something of lasting value and significance to the world. CHOOSE to what YOU want to do and do it. I know you think and dream about what you truly want for yourself. And we can ONLY dream of things that are possible for US. Even if it has never been done before. We have too much evidence to deny that living a life of great significance, regardless of where we started or are at currently at in our lives. What we have or don't have. What we know or don't know. Open your eyes when you look in the mirror and FACE yourself. Stop allowing the unimportant to prevent you from the important. You have greatness in you. I don't believe this, I KNOW this. Never, never, never give up on yourself.***