We do not always know what motivates a person to do what they are doing.
For someone to be begging or looking in the dumpster for foods, even though we think they have enough money, can be presumptuous, judgemental thinking on our part without fully knowing all the circumstances regarding that persons life.
Listening to your gut instinct before giving especially money is a wise thing to do, however when it comes to other things like food or clothes... if you can, give to them if you have anything to give .
For sure, psychological problems, like depression low self esteem,low self worth can have a lot to do as to why someone is begging or looking into dumpsters for food or asking say for example, a fruit store is they can have the fruits and vegetables that are going into the trash can anyway or looking for clothes or other.
when a person has been emotional/psychologically shattered, many times they no longer believe in themselves , they believe more the lie that they are worthless, and rejected by society, and live with that cloud. Many such cases, for the rest of their lives many times they go to their graves like this.
Definitely taking the time to try and have a conversation with the person, and if possible direct them to resources that could better help them. And when it comes to people begging for food or looking into dumpsters for food. Many times a deeper reasoning than just trying to get things for free without having to pay it is underlining their feeling and their state of being in being poor. If a person THINKS they are poor, they are poor indeed.
1to3's post in Question about giving to the poor. was marked as the answer