Economic inequality elicits widespread concern, yet those most affected—non-affluent individuals—often remain less politically engaged and knowledgeable about policy solutions. In 2024, Austrian millionaire heiress Marlene Engelhorn launched 'The Good Council for Redistribution', a private deliberative mini-public tasked with redistributing her €25 million inheritance to address wealth inequality. We conducted a field experiment around this event to study whether participation empowered council members to become informed advocates for progressive taxation. From 10,000 randomly invited Austrian residents, 50 individuals who expressed interest were selected as council members. We compare these members to both a control group of interested non-participants and a representative sample of Austrian residents. Council members and the control group completed three survey waves (baseline at the selection stage, pre-treatment, post-treatment), while the population sample provides post-treatment benchmarks. Our findings reveal that while participation increased knowledge and facilitated consensus on wealth tax design, it did not boost political efficacy or inspire greater political engagement. The strong pre-existing egalitarian attitudes among participants limited the potential for significant attitudinal change. These results underscore the challenges of privately organised deliberative initiatives in fostering diverse perspectives and sustained political mobilisation.