Feed the birds scam
If you are in Rio and you are near a park or historical part of the city and someone gives you a bag of seeds to feed the birds. Keep in mind that you gonna be charged for this bag of seeds. Most of the time the scammer will ask you a crazy amount of money but he will be happy you give him a couple of bucks. Anyway, there is no reason to fall for this scams. Each time someone handles something just smile and deny and keep walking. There is no reason to put yourself in trouble.