mmm...I guess each is justified by their intentions and rationale for thinking the way they think. There is no absolutes as one chooses to see and justify their actions.
The scary part of one assumption as 10Der correctly mentioned is that a photog must not be afraid to bring a camera out to shoot; it is irrelevant whether the photog brings the camera to his eye level or shooting from his hip, or for this matter, his chest. The act of taking photos is not inherently wrong. The intention of taking photos cannot be assumed to be wrong (in a very Singaporean sense of <guilty until proven innocent>). We can all be responsible citizens in any society, but each must not attempt to overextend our self-righteousness. Furthermore, I dread the day when each and every act must be written down and preapproved before we can do it <aka no U-turns unless we see a U-turn sign>.
Therefore,
1. the fat ass is not wrong to take pictures; whether it is of stone chairs or people, or pretty looking girls; but then if his subjects are political/security sensitive locations/people he can be invited for an interview and those film conficated/digital images deleted.
2. the fat ass have to stop taking their pictures when asked to; if he does not, the subjects can file charges of harassment. Or the police may simply charge him for being a public nusiance.
3. the fat ass do not have to delete if he do not wishes to legally (subjected to point 1); because he created those images, abeit unwilling subjects. The subjects may seek injunction to stop him from selling/posting those pictures (if they can prove that his actions have indicated that possibility)
4. the fat ass can be ordered by the court to stop selling or remove the postings (note: it is irrelevant whether the pictures are offensive or pretty)
5. the fat ass can tell everybody that he wants to shoot upskirts of the subjects; as long as he have not done it or caught doing it, he has done nothing wrong. Only shows that he is an *******/jerk, and there is no law against that.
6. the Singapore law enforcement CAN visit the fat ass home and find things incriminating him in many other offences with just a "suspicion" unlike the USA (they require a court order; and the court require proof; and can only use the relevant evidence found but not other incriminating items for other separate crimes)
Of course, if you replace "fat ass" with "photographer" changes our thinking quite a bit. Though I am not lawyer, I learned all these shooting in Utah, LA, NY through other photogs. Common sense do not vary very much, only the application of the law.
Hopefully this helps a bit.