These guys had my email address and could have sent a detailed response. Instead, they sent a short (but clear) one. If they actually wanted a phone interview, they could have asked for one and provided a number to call. And it's possible to send more than one tweet if they wanted to respond that way.
They did link to a FAQ which isn't clear, and their Terms of Service is posted on the page as others have noted. This is what raised my eyebrows to begin with and why I started asking questions.
A friend who is a tech reporter said "When they're responding like this, you know you got 'em." Given that Rory has had all morning to dispute any of the facts in my blog post, and has not done so despite being very active on Twitter, it seems clear that my reporter friend is right.
If the answer "Are couriers covered by Common Cartier rules?" were "no", the extension is: "No, totally no, 0%, zero, nada, zip!" [fake quote]
Their answers to "Are couriers covered by Common Cartier rules?" is something like: "They will get a seat in the plane and can use the bathroom." [Also, fake quote.] They are not replaying the question, only stating something unrelated.