Is it the one which warns the viewer about distressing scenes? they say that at the beginning of CSI too.
At the beginning of 'psychic' shows such as John Edward & Colin Fry they say something about the shows being for entertainment purposes only, and that opinions vary regarding the nature of clairvoyance & clairaudience.
I suppose it is the channels way of clearing themselves in the event of anyone wishing to sue for damages in cases of stress or fear!