I think there's an issue with people thinking the person is faking it.
There's a world of con artists out there, and they'll stop at nothing to find the sucker that was born, in order to take advantage of them.
How many times have I been approached by someone that says "Excuse me, um, my car is right over there with my family. I'm from Oklahoma and we drove here looking for Oakland but ended up here in SF instead. I'm out of gas and just need $5 to fill up. Can you please help me?"
Why would you cross the bridge from Oakland and drive past the destination across the water?
Why would you come to Oakland, conveniently with "just enough" gas to make it to Oakland, but not have enough money to fill your tank again?
They say "excuse me" or "pardon me" or something to put you at ease, when it actually does the exact opposite.
We've heard many people beg and barter for our money, the money we decided to get out of bed and EARN by getting a job. But we've become desensitized to people actually falling ill or being in need of help because of all the people abusing us when they don't need our good graces. "One bad apple spoils the bunch" they say.
I'd bet that many people, whether they're willing to admit it or not, are afraid to be taken advantage of. Either a candid camera prank, getting a gun pulled on them and robbed, or just being embarrassed at the fact that the person might be narcoleptic or something.