[timwiseman]

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.

I don't see why it seems wrong. They may not want you to record it, but if they are doing it in a public place they expect (or at least should expect) to be seen. Having it recorded is little different from having it seen except you now have a near-perfect copy to show others instead of having only the ability to discuss it.

It might to a degree be rude to record it, just as it would be rude to stare at them for prolonged periods as they did it, but that is very different than either morally or legally wrong.

Now if they are in somewhere that should be at least partially private (they're own home, a hotel room, etc), then recording is a very different story.