They only didn't for Demi cause she lived in a Sober house. I haven't heard of other examples.
They've never used the judges actual houses as far back as I can remember. They usually just rent a mansion or something. It's like that in the UK too. Also when they talk about it they don't say 'I put you through to my house' they say 'Judges houses'
Demi Lovato - Unbroken sold about 374,235 DIGITAL since nov. 2011 copies ww (my calculations using Kworb website)
Demi Lovato - DEMI sold exactly 158,739 copies ww (my calculations using Kworb website)