The iPhone 6 is apparently the only "secure" smartphone available currently.

[WelshBloke]

Did you happen to catch the story that LG was monitoring the viewing habits of customers using their smart TVs? Sending data to LG on what channels they were watching and what apps they used.

I'm going to guess that everyone else does that as well.

But that's a bit different to the voice recognition issue. That's just the way that voice recognition works. The device captures your voice and sends it off for off site analysis.
I think that one of the main problems is that people have no idea how this stuff works plus there's a bunch of click bait sites that love to sensationalise everything.

 

[Rakehellion]

Not a smart idea. A local police may lack a sophisticated expertise to hack encryption, there surely are policemen using iPhones with fingerprint scanner, which means they know how it works. You are likely to add obstruction of justice to your charge.

Obstruction of justice is a much easier charge to beat than operating Silk Road or whatever it is they're trying to find on your phone.