[caoilte]

> One limiting factor was that this wasn't scalable - so a lot of people would be comfortable with it because there is little potential for widespread abuse - there just aren't enough resources to search & monitor everyone's mail and houses at all times.

It's recently started to emerge that US opened and censored all international mail 1950-1989. We're talking millions of letters a week. It started as a measure to remove all reference to US use of biological weapons in the Korean War and grew from there. (the third season of the Blowback Podcast did a couple of interviews which covered it really well.)