Crowding is now one of the most common challenges facing major destinations. In places such as historic medinas, narrow streets become difficult to navigate, and popular natural attractions receive more visitors than they were ever designed to accommodate. Most flow management systems still rely on centralized data collected by separate operators, making it difficult to get a full picture or react quickly when congestion builds up. Transparency is also limited, and tourists themselves are rarely involved in the process. In this work, we explore Tourists-as-Nodes, a participatory approach where visitors can voluntarily share anonymized mobility data through their phones or IoT connections. Data are stored on a blockchain, which ensures integrity and allows automated responses through smart contracts. These responses can include simple alerts, redirect suggestions, or small incentives for visiting less crowded areas. Although research connecting blockchain, tourist flow management, and participatory data sharing is still limited, our framework points to a path toward more transparent, trusted, and sustainable tourism governance.