Was EVERYBODY an informant?

Actually, Caifano, whether or not an informant, wsas a "law abiding citizen" in a way:

His was one of the first names to be entered into Nevada's notorious "Black Book"--a list, maintained by the Gaming Board, of people who could be barred from entering, much less owning or operating, a casino because of criminal records, association with known criminals, or "unsavory reputations." Caifano flaunted it by crashing various casinos in October 1960 and intimidating the owners into letting him enjoy shows, dinners and gambling (he was finally ejected from Moe Dalitz's Desert Inn. He then filed suit in Federal court against his being listed in the Black Book, claiming it violated his right to "due process" under the 14th Amendment to the Constitution.

A Federal Appeals Court in 1962 rejected his suit. In a landmark decision, the court ruled that since the Nevada gaming industry was so vital to state's economy, and such a target for organized crime and other criminal elements, entry into casinos and casino hotels was a "privilege," not a Constitutionally guaranteed "right"; owners and managers could reject anyone who was in the Black Book. Caifano's lawsuit, in effect, validated the Black Book and helped the Gaming Board keep out OC figures.

BTW: Your driver's license is a "privilege" extended to you by the state, not a "right" protected by the Constitution. That's why you can be convicted of DUI on the arresting officer's testimony alone, even if there's no empirical evidence against you because you refused to walk a straight line, or take a blood or breathalizer test.