Re: fingerprint
It can't happen, it's been discussed to death.
In order to get the first imprisonment, the prosecutor (in the UK) has to demonstrate beyond a reasonable doubt that the person withholding the password, is indeed in possession of it. They have to prove that the person accessed a device within a recent period, so recently in fact that it's highly unlikely that the person could have forgotten the password. In cases where people have been imprisoned, the prosecution demonstrated using forensic data that the devices were accessed several times over several days all within the time frame leading up to the arrest and they have actual physical evidence proving that. "It's his device, he must know the password" is not and never has been sufficient evidence that has lead to a successful prosecution.
The idea that someone can be prosecuted a second time for the same offence say 2 years after the original prosecution is laughable. Courts have an understanding of the reliability of testimony from memory, and how it becomes more unreliable over days, weeks, months and years. Courtrooms (in the UK) are not like they appear in American TV dramas, where each interaction is tense and full of suspense with sharp back and forth dialogue, each word being met with surprise and an intake of breath from the jury. The prosecution never dramatically pulls out the final piece of damning evidence at the end of the trial that results in an instant "Guilty" from the Judge. No instead courtrooms are dull, methodical tedious places where previous policies, judgements and precedents are all brought up sequentially and legally argued over. Everyone and their dog in the courtroom understands the concept of degraded memory, and none of them would bother to try to argue that someone claiming that they have forgotten a password they last used over 2 years ago is lying. In fact for a prosecution to even begin under section 49 of RIPA 2000 specifically for withholding a password, a judge needs to first give permission to prosecutors to issue the notice of disclosure. Unreliability of memory is already an established and understood precedent so a second prosecution would probably fail at the first hurdle of trying to convince the judge to allow it to happen after such a long time.
So yes, it's a myth, In the 15 years since the law came into force it has never happened or been attempted. Where prosecutions have occurred, it has only been after physical evidence has been presented that has proven beyond a reasonable doubt that the person must reliably know the password being withheld.