my personal experience.
This bugger sells tissues at a well known eatery in the south. If
you dun buy, this bugger may say some sarcastic things, then say
"if you dun buy its ok, I'll still pray to god for your
safety".
Another bugger, always dressed well and loiter around around my
housing area. She look like any normal auntie. She'll then ask you
for money to take bus, or say she is very hungry and had never ate
the whole day, ask money for meals. There was once she kept
pestering a secondary school kid at the bus stop till the kid show
her his wallet. I was empty.
Another bugger, I met him near my ex-office (raffles place).
Usually dressed in an old polo and dirtied jeans. He'll stop you
and ask for directions. Asking how to WALK to ang mo kio. Naturally
you'll tell him impossible, take a train/cab/bus. He'll then looked
troubled and say he do not have a single cent and borrow money from
you, claiming he haven't ate and need to urgently go to his mother
who fell down in amk.