Sickness funds are starting to use digital behavioral data to encourage physical activity among their members, but the ethical and societal implications, especially in solidarity-based insurance systems, are not well understood. While these programs may foster new forms of solidarity and lead to efficiency gains, they also pose risks such as penalizing vulnerable groups, creating deadweight effects among already healthy individuals, and potentially undermining solidarity between different insurance systems. This study highlights the need for a deeper discussion on the effects of integrating eHealth innovations into healthcare frameworks.