…there is a twofold requirement, fi

…there is a twofold requirement, first that a person have exhibited an
actual (subjective) expectation of privacy, and, second, that the
expectation be one that society is prepared to recognise as ‘reasonable’.
Thus, a man’s home is, for most purposes, a place where he expects
privacy, but objects, activities, or statements that he exposes to the plain
view of outsiders are not protected because no intention to keep them to
himself has been exhibited.