The single most important thing to know about surveillance is that the overwhelmingly most common use of the resulting information is for extortion. Police and prosecutors use it to force (often false) confessions, or to coerce people into dangerous situations. Spooks use it to force betrayals. "Fixers" use it to force people harmed to drop legal actions.
The surveillance used for these things doesn't need to be about you, to harm you; it could be about a member of a judge's family.