To donate or not to donate?

Just now, on my way home, I was waylaid at Raffles City by a guy who purported to be authorised to collect donations for an orphanage by NCSS (he displayed a paper certificate & his IC). He was rather aggressive and I declined.

Not that I'm unkind or anything, but I'm usually quite suspicious of these street collectors and if they're for real. I think I used to be a bit too gullible and I believe I must have been bluffed a few times (considering the news articles that says some are frauds). After all, paper certs can be forged...well then that's another legal matter altogether. So now, my policy is to donate only in 2 situations - either direct to the organisation or those school flag-day event. I think that's safer (despite of the NKF incident). Don't want to benefit those syndicates you know in case it is really fraudulent.

Anyway, coming back to the guy, he actually tried to convince me again, but I declined yet again. Maybe I had looked like I was softening up and probably like those that can easily be persuaded, so he tried again. After that, he was very frustrated.

As I was walking away, in a way intimidated by this person, I'm not sure if I heard wrongly or he was saying something else to his counterpart not far away (probably I heard wrongly), I thought he said "sadist". I was a bit shocked & as I looked at him, he said it again, though he wasn't exactly looking at me. So I was quite upset after that, although I might have heard wrongly, coz the word doesn't really fit into the context (not donating to the orphanage = sadism???).

In the 1st place, I don't think they're allowed to collect monies like this in the shopping centre. Secondly, if people don't want to donate, should they behave this way (if I did hear correctly) or try to force you to donate?

Anyway, should we donate or not? There's always this conflict of whether it's for real and the feeling of guilt if it is for real and you didn't donate.