It seems to work in the US. There's a man in Philadelphia, who's been jailed for years. He's charged with contempt of court. because he claims to have forgotten the FDE key for his macOS box. Which investigators believe is loaded with child porn. And so he periodically sees the judge, who extends his sentence for contempt. There's apparently no limit under current US law.
Well, a lot of people live in EU jurisdiction. And at least until March 2019, a UK warrant can cause you to be arrested by any EU police if one of the crimes covered by the warrant is also illegal in the country where you're arrested.
I don't think somebody living outside of UK cares. The threat only wors if that person lives in UK jurisdiction. Not everybody does.