Why is someone who is collecting disability out there working on the sly?

Someone collecting disability might work "on the sly" due to financial necessity, as disability benefits may not cover all living expenses. They may feel a sense of guilt or shame about their situation and desire to maintain a semblance of independence or normalcy. Additionally, some individuals might believe they can manage both their disability and a job without risking their benefits, leading them to take on informal or under-the-table work.