In the past months, there has been a lively debate about so-called COVID-19 apps developed to deal with the pandemic (Morley et al. 2020b). Some of the best solutions use the Bluetooth connection of mobile phones to determine contacts between people and therefore the probability of contagion, and then suggested related measures. In theory, it may seem simple. In practice, there are several ethical problems (Morley et al. 2020a), not only legal and technical ones. To understand them, it is useful (...) to distinguish between the validation and the verification of a system, remembering that these words are used here only in the design/engineering sense, and certainly not philosophically. The validation of a system answers the following question:“are we building the right system?”. (shrink)