But they’re automatically blocked… unless they open their minds to scans, which I suppose they might. Source? Is it mentioned in Alien Module 4? I was always the impression that only proles were scanned.
Thought Police monitor all of Zhodani society, conducting
periodic examinations of individuals in order to ensure that
everyone's mental health is at acceptable levels. But the
Thought Police also conduct random sweeps of the community,
looking for signs of unacceptable behavior or deviant thought
patterns. When they find such patterns, they seek them out,
find their source, and remedy the situation.
A psionic with Shields blocks Read Surface Thoughts and Probe attempts. A person's emotional state can easily be read unless someone is exercising extraordinary control over them. For most people, this requires conscious thought to do. A highly disciplined person 'defaults' to a poker face, but the emotions are still there. When the Tavrchedle' encounters someone with Shields, they have to talk it out with them instead of Read Surface Thoughts. They can request that the Intendant or Noble drop their Shields, and this is most often automatically given, but they don't instantly attempt to Probe every person who is angry about something.
Here's how it would play out on a Zhodani world:
A Tavrchedle' officer is patrolling and senses intense negative emotions. She investigates and find that they are emanating from a Noble. The officer is an Intendant herself, but she's within her authority to inquire whether the noble is alright. The noble, who is going through a romantic breakup, does not perceive the Tavrchedle' officer as an intruder or a threat. On the contrary, the Tavrchedle' is seen as helpful presence, like a paramedic or a police officer at a traffic accident. She cannot automatically Read Surface Thoughts on the Noble, he has shields. What's more she doesn't have the authority to do so. The Noble has the right to mental privacy. But she gently asks what's going on and the Noble engages with her as a counseling patient. The Noble hasn't done anything that is illegal, he's just emotionally troubled, so the Tavrchedle' files an incident contact report and that's the end of the matter. There is no embarrassment involved, any more than if paramedic administered oxygen to you if you were hyperventilating.
The Tavrchedle' has two 'divisions', so to speak: the vast majority of officers are Civilians, charged with preventing illegal activity by engaging with the public about their negative emotions [anger, frustration, jealousy, desperation, vengefulness]. The second division is the Military Tavrchedle', which oversees military units and ship crews and also has a military intelligence function when deployed into combat zones or occupied areas. And these latter are the 'thought police' that are so often vilified in Imperial propaganda... the stereotype is a turbaned SolSec monitor, part KGB and part Gestapo, that mind-rips anyone at the drop of a hat.
There are no indications that “negative thoughts” can be detected in a fellow psionic. You’re blocked from detecting their thoughts, so why would you be able to detect their emotions? Psionic nobles and intendants are beyond reproach unless they voluntarily lower their shields and allow a probe. However, you could argue that occasional probes are allowed as as matter of course.
With psionics mechanics as written, it’s unrealistic to think that the Tavrchedl could scan everyone all the time, anyway. Their jobs are harder than that. They also need to be experts at reading non-verbal communication, a skill from the CT Zhodani book.