Support from the population has always played a major role in coping with disasters. Over the past two decades, technological developments such as social media and mobile devices have opened up completely new ways of organizing unaffiliated or spontaneous volunteers (SVs) and have multiplied their potential as a vital force in disaster management. However, coordinated cooperation between these volunteers and official disaster response organizations is often difficult, as they are not integrated into existing command and control structures. As part of our research, we developed an information system for the integration of spontaneous volunteers, enabling the use of various client systems. In this paper, we present initial quantitative results showing differences in technology acceptance among volunteers using a mobile app versus a chatbot. Results obtained during various disaster management exercises provide insights for the practical development of such systems.