Surely not always a joke. If, for example, a couple is kissing in public then recording them against their will seems wrong to me. Whether it ought to be illegal is another question.
OTOH it seems to me that the actions of police ought to be regarded as public acts, and recording them in the public interest ought to be legal.
>Keep in mind that there is a big difference between taking a picture and publishing a picture
Yes, although the person being photographed doesn't know what the picture will be used for and so he may feel constrained nonetheless.