Unfortunately, the type of charity scams happen way too often. They are rampant here in Bulgaria, too. One of the worst things I know about is when homeless beggars actually have managers who collect their "earnings" under the threat of violence. That's why I'm sometimes weary of leaving them money, but I'm always happy to buy them a meal as this is something that cannot be stolen from them at the end of the day.
We should always do our due diligence before giving, but this shouldn't mean we never give. After all, everything comes with its own risks in this world.