The continuous monitoring of the performance of telecommunication services is a necessary tool of the maintenance and improvement of service quality. QoE feedback procedures relying on human evaluators are considered to be one of the most important industrial inputs in the field of services. Distortions regarding this input require additional attention due to their ability of making measurement results inaccurate and misleading. This study aims to observe and analyze the effect of specific environmental information, which is commonly public to the evaluators. The performed series of measurements demonstrates how the awareness of the type of connection can make constant objective quality to result in a rather varying subjective quality. Along with the overview of the mechanisms of cognitive and post-decision dissonance creating the distortion phenomenon, numerous common and uncommon evaluations performed by measurement subjects are detailed. In order to support understanding evaluator behavior, measurement subjects were distinguished by Level of Comprehension, based on prior technical knowledge and experience. The given service was displayed on a 3D tablet PC.