Say some strangers walk to you and would like to sell/promote/suggest/blah blah blah something to you, please, I know you have a better common sense that it is a scam. Recently I got down from bus at Bandar Tasik Selatan station, because I was travelling north from south, and while I walked to the LRT station not so far away, standing along the only path were some Chinese guys holding some sort of paper/flyers asking you CHINESE to stop for awhile and listen to their crap stories about stuff they wanna sell you.
Well here's are my suggestions on how to handle these guys or some similar situations.
1. Just keep on WALKING. Why stop at first place???
2. Assuming you are with your friend(s) and from quite far away you see these people looking suspicious already, then tell your friend(s) to stop talking(if you are talking happily that moment) and just walk straight. If it happens that they separate any of you away, then just speak GOOD ENGLISH. Stuff like "Sorry I don't know what are you talking about" or "Sorry I don't know Chinese" in British slang(just kidding) might work. If they can speak a little bit of Manglish, so you reply stuff like "You'll see, I'm in hurry, so thanks but no thanks" and get your ass out of there real fast and don't look back!
3. Maybe you can try saying "Saya bukan Cina la..kulit putih aje.." and of course, walk away!!!
Or sometimes while you are eating in some place, some people will come to you and wanna ask you to be good Samaritan to just buy their stuff/do their survey/etc etc etc...
4. And again, and of course, why at first place do you want to pay attention on it?? JUST SAY YOU ARE NOT INTERESTED!!! Ask them to leave, or you leave, quickly.
5. If it happens that they say they are students competing or anything, outsmart them. Ask them for their STUDENT CARD, although they might have a fake student ID but no worries. Take their card, if possible snap a picture of it or if not, try to see which college/university they are from. Ask for phone number of the person in charge too if you can. I tried and it worked, I mean, that person just took back the ID and went off. It depends on how you try to get information out of it. But of course, be careful, these people are smart too.
Maybe sometimes, in some cases, old people with teddy bears walking towards you and asking you to buy it, or some organisations approach you for donation and with some licenses, then up to you to believe their stories or not because some of them DO really doing it for good while most of them take this as an advantage.
You are smart, you know what to do. :)