@ Mark
I started re-writing that paragraph, got distracted, and then hit send without re-reading. Doh. :) The US, being outside the EU, isn't subject to VAT at all. The VAT treatment is identical - it's not charged, because the service is outside of the EU. The reason for mentioning the rest of the EU was to make the point that even where EU taxation *does* apply, the place that the worker is located is largely considered irrelevant for considering where the work is carried out.
I'd think "the European Union considers this outside the scope of its taxation jurisdiction" would give a powerful element of persuasion to the argument that the US should be allowed jurisdiction.
The US position on the "location of performance" for services such as electronic consultancy isn't something I know much about (not being a US-based company performing services to non-US customers, I've never had to look it up) but it's not really relevant; the US government is arguing that the EU should allow them to extradite, not that their own law gives them the right to. Nowhere (to my knowledge) has McKinnon's team asserted that the US do not have the right under their *own* laws to extradite him.
As for the working-vs-not argument, there are instances where work for hire is treated differently than "work for free" (whether it's desired by the recipient or not), most notably in terms of employment law, health and safety law and other statutes and acts which establish fiduciary responsibility. Otherwise, I'd think it reasonable to suggest that the same treatment should be applied regardless of whether the performance is in exchange of consideration or otherwise, and would expect the US to argue likewise.
In response to your other post, that it's "not a crime in the UK" is not my understanding. Our laws aren't particularly great on the subject of unauthorised access to computer systems, whether data is modified or not, but we've had laws against intercepting communications for decades which have been used to enforce network boundaries in the courts. And, regardless of where he is at the time, the system he was working on resided physically in the US.
To put it another way... what if he was a telecommuter, working for a UK bank, servicing your personal account, and appropriated all your money for his own pocket - but did so from a country in which the offence of theft requires the *physical* removal of an item rather than simply depriving you of it. Would you say his actions were lawful because where *he* was, they aren't banned by statute... or would you say they're illegal because he's working for a UK bank and in THAT jurisdiction it's unlawful? For me, it's the latter every time. I work remotely a lot, mostly from Egypt... and I certainly expect to be held accountable to the legal framework of my clients rather than the warm and sunny country I choose to sit in while doing the work.
Kev