The publication presents potential places of conscious or unconscious interference or degradation of data collected using a distributed system of sensors and/or other IoT devices. Places of possible interference in the measurement data are indicated from the very beginning of the measurement chain – from a single measurement element, through data conversion, transmission, processing, storage, analysis to interpretation. Threats are indicated not only of technical but also economic nature. Examples are presented that are intended to show how the flow of data can affect decision-making and how the lack of knowledge about the measurement context can affect their interpretation. Possible anomaly detection mechanisms are also indicated, considering new, developing techniques.