Due to the complex and relatively unpredictable nature of human behavior, customer service-based processes such as those featured in call centers, restaurants, and hotels can be challenging to model. The present study provides an example of using established theories of customer behavior, in combination with primary data collection, in a time and cost efficient way to model customer decision-making in a particular situation. The context of the study is a hotel check-in process manned by three service employees to which management would like to add a self-service check-in alternative, in order to reduce waiting times. In order to model how customers choose between using the service employee and using the self-service technology, a crucial component of the simulation model, scenario-based surveys are used to supplement existing theories. The simulation study is briefly described and the advantages of this approach are discussed.