Well, that's just it. It was announced as, and should only work as, the ability to scan for wifi hotspots using a random, untraceable MAC address. This is because advertisers and other third-parties were beginning to use wifi hotspots as passive ways of collecting unique IDs for devices (their MAC addresses). So under this system, when it works, walking by a hotspot shouldn't identify you to it if you don't auto connect, while actually connecting would.

Edit: from their previous post:

In iPhone 5s, MAC randomization happens only under the following conditions: Phone is in sleep mode (display off, not being used); Wi-Fi should be ON but not associated ...

I would argue that the phone needing to be in sleep is also a bug. It should "just work"... Ideally even when scanning for new networks while associated.

One of the use cases I've read about is retail shops would record all devices within range (1 MAC = 1 user) and could get a good guestimation of:

- How many customers current in-store?

- How many are repeat customers?

- How often does [repeat customer] come in? List of dates and times.

- Manufacturer of their cellphone (e.g. Apple. Samsung, etc)?

Obviously this type of data collection has limitations (e.g. people without cell phones, with WiFi disabled, etc). They also cannot likely tie purchases to unique MACs (because cellphones scan infrequently, so detecting them as they leave through a register is difficult/unlikely).

However they can somewhat work around these problems by harvesting additional information from "apps" (e.g. install our app get a coupon!). The app grabs the MAC and now they can tie that customer's shopping behaviour directly back to the customer.

iOS apps are sandboxed away from reading the wifi mac since iOS7, by the way.

I wasn't aware of that. Unfortunately Android apps have no such restriction [0] and don't require any special permissions [0]. That iOS 7 change is likely along the same vein as Apple's addition of MAC randomisation: trying to disrupt such tracking.

I'd wish Google to follow suit, but let's be frank: Tracking people is Google's bread and butter. They're more likely to sell MAC addresses to advertisers than they are to randomise or otherwise restrict access to them.

[0] https://stackoverflow.com/questions/6064510/how-to-get-ip-ad...

It does appear to require permissions, as documented in that answer. Apparently it only needs INTERNET[0], which could qualify as "don't require any special permissions" as you say. INTERNET is disappointingly broad.

[0] https://stackoverflow.com/questions/16127263/networkinterfac...

Well, randomization was what everyone initially thought would be the case always.

So it's disappointing to find that it's only going to randomize in specific, somewhat unusual modes. :(