I rewatched TSOD recently as well. Reminds me of a science fiction story I read ages ago where the world was totally dependent on such transmat type devices. Houses didn't even have doors anymore, which caused all sorts of problems when things inevitably go awry. I wonder if Who was inspired by that or the other way around?
I don't think Autons were ever used to impersonate real people? I really need to get my hands on some Tom Baker stories before they go out of print.