I have just spoken to a friend who is one of the UK's Data Protection guru's and apparently he believes that some spyware may contravene UK DP law to the extent that he is looking to put together a paper on the subject for publication. If his initial assessment is right, then any spyware/trackers which are downloaded from, or, pass through any UK based servers could result in the owners of those servers finding themselves in court. The key thing here is the pass through, so all those UK based ISP's are potential targets for the knock on the door.
Of course, for the ISP's etc., all they have to do is include a statement of 'you will be tracked' in their T's & C's and make a positive opt in part of the process and they are in the clear. , , and if we all bothered to read the registration T's & C's, then we would at least know who is assisting the spammer.