No, that’s not what ‘prisoner’ means. My dictionary says it’s either someone in an actual prison, “a person captured and kept confined by an enemy, opponent, or criminal”, or “a person who is or feels confined or trapped by a situation or set of circumstances”. Those definitions are close to what I had guessed the definition of ‘prisoner’ to be (“trapped or restricted in movement”).

People who are constantly being watched may be prisoners in that they feel trapped by the surveillance, and limited in the actions they can take, but that is not an instrinsic part of being watched. Some people being watched are prisoners, but not all. You want a word that means “people under surveillance”. I don’t think there is any such single word, like ‘surveillee’.

Do you not feel trapped or confined by the breaches of privacy commited by the government? That would satisfy your definition.

As I said in my second paragraph, feeling trapped or confined by the breaches of privacy commited by the government “is not an instrinsic part of being watched”. It doesn’t matter whether I personally feel trapped or confined. As long as there is someone out there who is “constantly being watched” yet does not feel trapped or confined, then that means “someone who is constantly being watched” is a bad definition for ‘prisoner’. And I’m sure there are people out there who don’t feel trapped or confined by the government’s surveillance.