1. Apple is making nothing off this. Seriously. $1.99 per n-shipped Mac, even if they got it, barely (if indeed it does) covers the cost of administering the deal. It certainly doesn't cover the "bad blood" relationship poisoning due to the program (which Apple knew full well would come about; you can't charge money for something without someone getting ticket off, even if none of that money actually makes it to your bank account).
2. It's the cheapest 'n' hardware you'll ever get. $2 to upgrade your computer from 'g' to 'n'? I'd gladly pay that, although I'm afraid my old non-Intel book isn't gonna make it.
3. The complication here is that Apple shipped hardware that cost extra, was disabled, and was unadvertised but discoverable. This is why we are in an accounting gray area. This is not a standard software update, nor is it a standard firmware update. It is enabling hardware that they never "sold", that cost them money to ship, and that one could argue drove some number of sales of its computers (because in some circles, like here, the 'n' capability was widely known). The argument they are guarding against is that of someone who bought with the understanding that 'n' capability was being shipped with the machines, with the knowledge that Apple had no reason to ship 'n' hardware unless it expected to use it. Then, that person didn't 'receive' their logically expected hardware until this quarter, well past when Apple reported the revenue. This is a no-no in GAAP, and explicitly illegal under SOx (for those wondering why they first said SOx and now say GAAP).
4. These general accountants, I am sorry, do not share any of the culpability Apple has if it does this wrong. Apple's being conservative here to avoid issues down the road. They've got enough current issues to deal with (which are due to following "standard" practices that many, many accountants tacitly approved in the previous ten years) that they don't need to risk more press time being spent on another "scandal" instead of their products.