It seems to be routine for rape complainants to have to hand over their phone and have their messages scrutinized, as a pre-requisite to proceeding with an investigation. That is a form of government blackmail.
I disagree entirely with that notion. If you make a serious accusation, you must be prepared to hand over the necessary evidence to assist the investigation and get a conviction. I'll also say that at that point, the risk has changed dramatically. Risk isn't a static thing. It needs to be assessed regularly and evaluated when your threat model changes. Your exposure to risk is still a factor.
Of course. But you shouldn't have to spill your guts about your entire life (I understand that young folk nowadays life their lives in Instagram selfies).
And more to the point, the first step for the policemen investigating a rape complaint should be to investigate the complaint, not the complainant. If the investigation of the complaint raises questions about the complainant, then there might be grounds for seizing the complainant's device. But they can't make device seizure a pre-requisite for doing their job.
This is rubbish. The police investigate the claim and based on the results of the investigation, the prosecutor decides whether charges can be laid. The prosecutor!
What? Where is this routine? Where do you live? What if you don't have a phone? Why would you give your phone to the police in this situation instead of the prosecutor?
Which government? What level? My god, who told you this thing? For what other crimes is this policy enforced?