[jand]

> They will get all the data collected by the service, which is none.

(disclaimer: not rooted in knowledge, but in pessimism)

If the web service / whatever cannot provide the requested data, it would be in violation of the order.

So all you really need are harsh fines for not complying with the order and the problem morphs from a technical one to a business decision.

[kvdveer]

Under current law, you cannot be compelled to share more data than you're already collecting. However, the term "collecting" is a bit wider than the most common use. If you receive some piece of data, you are collecting it, even if you don't keep logs, or don't do anything with it.

It's not much different than how detective work is done in the physical domain. You cannot be compelled to ask a customer for more info, but you can be compelled to share info that the customer gave to you, even if you didn't ask for it or never wrote it down.