The fairest way?

We do seem to be awash with paranormal investigation shows (no bad thing as I like them) but all the programmes who use mediums as part of their investigations always have one fatal flaw - previous knowledge of the location, and hence it's history. I would love to see a firm of well respected and trusted lawyers who are sworn to secrecy actually arranging and then choosing the locations for investigation. Then vans/cars are sent to pick up the entire crew who are waiting in a designated location, unaware of where they are about to be whisked off to. The insurance and all the red tape will have been sorted out in advance and the entire crew will be driven to the location in vehicles with blacked out windows until they arrive at the destination.
OK, there may still be some "contamination" if any of the participants know the said location and building, but it would cut out a great deal of the suspicions about the prior knowledge of the mediums. There would also be an off-site historian who DOES know the history, and who is listening live to the crew as they do the investigation and can report back on the accuracy (or otherwise) of the information the medium is coming out with and report this to the audience. The team on site wouldn't know what was being said.
This may all sound a little brutal, but if mediums are to be used there have to be proper scientific controls. Give me prior knowledge of a location and I reckon I could be quite convincing about my conversations with the afterlife!