I'm confused by your reasoning here. If we agree that the files are definitely on the system how is it a "fishing expedition" to want to see those files for further investigation. A fishing expedition would be forcing everyone to submit their devices for inspection on the off chance of finding evidence - this case is one where the evidence is known to exist and a person is refusing to hand it over.
The less emotive case would be the hard drive contained bank statements for tax avoidance - and I would still think that a court should be able to compel someone to produce that.
The less emotive case would be the hard drive contained bank statements for tax avoidance - and I would still think that a court should be able to compel someone to produce that.