Although the OP case is different, but people do not under this as they think that gambling gives much higher returns, which is not true most of the time. Secondly, sometimes the other person also convinces that he is a good gambler who has techniques and skills to always make money in gambling. He may use fake screenshot proof to convince the other part and get money from them. People are already disappointed with their own performance in gambling so they agree to give their money to other person although they do not know that the gambling results won't change much.