As a rule, the phenomena of physical mediumship take place in the dark or in very dim red light in specially equipped séance rooms. Control measures are either not set up at all, are determined by the mediums themselves, or are otherwise inadequate: the perfect playground for fake mediums.

The founder of the IGPP, Hans Bender, was already able to uncover obvious fraud under the circumstances described. Because little has changed in the practice of physical mediumship to this day, this is still possible today. Many seemingly impressive experiences during these sessions are based on quite trivial occurrences – although this is not always acknowledged by gullible participants in these sittings. Even if there is clear evidence of fraud based on photographs, video footage, re-enactments of the tricks using conventional means, self-contradictory statements by the mediums, etc., many of their followers do not want their belief in the authenticity of these phenomena to be taken away – a perfect example of the power with which personal convictions can limit the ability of self-criticism – and another reason to point this out occasionally from the perspective of mental health.