HN user
The EFF has been doing some good work on TOS abuse. https://www.eff.org/issues/terms-of-abuse I'm sure they would be interested because this linking policy is absurd. There is no way a practice like this would be 'illegal' anywhere but on Apple's app store where I imagine Wolfram Alpha holds at least a little sway.
So Apple wants to block companies from allowing people to see content that wasn't paid for through their system. What's next, blocking paid websites?
Surely Amazon would just set up a website where users could access their Kindle books, bypassing the whole App Store problem. This is silly on Apple's part as it decreases the potential audience for their devices, and the ease of use.
I'm still on the fence about that whole cloud thing, personally.
The problem with this idea is that if a distinctly 'human behavior' can be calculated, it can be emulated. Also, it would require a lot of JS and other support that some people don't have. There's also the problem of false negatives when you consider auto-fillers that a lot of people use.