A very important point to discuss. While I don't know specifically his change of behavior there are more widely known cases to discuss.
For example Soviet Union and East Germany. I can tell you that the behavior of people was different, especially on the phone where part of the surveillance took place. Youth, being mostly ignorant about that in some cases got their parents in trouble which in turn affected parents' behavior at home.
I think the takeaway from these and other cases is that public's change of behavior is function of security services' activities (corrupt or not). All it takes is several known cases of visits from the authorities about things one said over the voip or im conversation. Or the authorities pressuring their catch for money or cooperation in unrelated case to 'help them out'.
I also think this directly affects how free we feel. If we would constantly have to guard what we write in e-mails as to not to be remotely connected to what might be seen as mentioning the current enemy of choice, then some freedom is lost.