> but there's more nuance than just theft of CPU cycles or services.

CPU time, network bandwidth, storage space, the infrastructure to drive the rest, the fat, fat internet pipes to handle half of the United States' text messaging demands...

> For sake of argument, I'm deeply embedded in the Apple ecosystem. I have a half dozen devices that are all capable of communicating via iMessage. If I want to bring an Android device into my personal ecosystem, it doesn't seem clear ethically or morally that there is some theft occurring. I realize there are other scenarios where someone has no Apple devices, never intends to, and would be in a weaker position, having never "bought in".

The ethics aren't the issue. The stealing isn't a problem because it's morally wrong; it's stealing because it's against the terms of use. It doesn't matter if you own 150 iPhones and 1 Android: the iPhones meet the requirements, the Android does not. And Apple has no legal, ethical, or market obligation to allow it in, they just don't. You can text the Android from the iPhone and vice versa and it will function completely correctly in both directions, with full support for the open protocols.

> I'm bringing this up primarily because there is a whole ecosystem of products that exist based on brute force workarounds to a lack of public APIs. The existence of this kind of tech would equate to similar kinds of "misuse" if only judged based on whether or not the service provider intended for this use case and whether or not the client was using some publicly blessed integration channel.

I think you're free to do it and the provider of the service is in turn, free to make your workdays a living hell in a never ending escalating pattern of back-and-forth modifications, or free to ignore you if they don't care. Quicken apparently doesn't care, Apple does. Those are respectively their responses and both are right depending on the organization's priorities.

Most web-scraping I see is pretty gray on ethics too though, things like the stack overflow clones that piss all over the information with ads and try and SEO themselves in front of the posts they're ripping off. Personally I think all those web operators can locate a fire to die in.

> I think it's reasonable to say that in some scenarios, such use could be classified as misuse. But I don't agree with a blanket statement that "using undocumented APIs is misuse".

This is not undocumented, it is documented and said documentation is kept private because it is not meant for anyone's use outside of the organization.

> Textbook misuse would be building an iMessage spammer bot.

And it could be easily made the case that this is exactly the reason why Apple demands you own Apple devices to use the iMessage service: Because it can't be automated on their own hardware, and because it can't be used by other devices/endpoints, it is much, much, much harder to spam via iMessage. In fact I'd say it's bordering on impossible unless you buy an iDevice and do it by hand, at which point, Apple can see your suspicious traffic and disconnect you from the network, possibly without you even knowing you've been.

That's not to say they couldn't secure it in a way to combat abuse, but again, why? What does Apple gain here apart from a happy nod from a userbase that is wanting to use an Android phone and an iPad? iMessage is a free service that Apple fans enjoy using. They gain nothing by making it open to people who don't use Apple devices, and that freedom for you comes at a security cost to the platform as a whole and the users in it. Apple is very clear that their priority (apart from profits) is their users, and this gains their users incredibly little while opening the platform to much wider instances of abuse that are already incredibly common.

And even aside of my views and understanding of systems integrity and API use/misuse, frankly, even just the anti-spam excuse would be enough for me to support them in this unilaterally, because as a service, iMessage is the only platform I make regular use of that I don't end up getting calls about my cars extended warranty, or messages from hot russian women who want to bang me, or people asking to buy my stupid house, or assholes telling me they've hacked my PC and are going to send videos of me jerking off to my family, or whatever the hell. And if the closed ecosystem is the only way to do that, which it kind of seems to be, then close the ecosystems I say.