They were kept without computers and internet access: https://www.bbc.com/news/world-europe-19711022

So it does happen, contrary to what you claim.

I don't have evidence but I do have experience on this.

I'm not sure why you would be the quickly dismissive of something that would seem obvious to many.

I knew a person who was in abusive relationships where the abuser would keep making ridiculous claims that the person was cheating on them, and made them give up having their own phone as "proof" that they wouldn't cheat.

Of course, the abuser was cheating the whole time.

I mean, it’s a ‘water is wet’ kind of statement. Prisoners aren’t provided a mobile phone and data plan either.