Candid does not mean "secretive and very guarded", though. People misunderstand the meaning of candid camera and assume it means "secret camera" and so use it that way, but that hasn't reached a level of misuse to redefine the meaning of candid.

Got tripped up by "candid" as well. Have always thought it meant furtive or surreptitious. Well, it's never too late to learn.

Surely it’s called Candid Camera specifically because it reveals something that would otherwise be hidden?

I thought it’s candid because the subjects’ reactions are honest, unrehearsed.

It is incorrect.

Uh, no.