If you do not look like a native, then you will be hounded by paupers/beggars. If you help one, generally onlooking beggars may come asking you for money as well.
The rule to respect would be to ignore anyone asking for money - a conversation isn't going to lead anywhere.
Keep yourself safe - do not make a display of your money. You never know who's looking at you and what they have in mind.
