In what situation is the Faraday cage most useful during the KP measurements?
The simple Faraday cage we supply will shield the equipment from electric fields due to the operator (the chair the chair they are sitting on), equipment on the desk and in the vicinity. Note an operator can be at a static potential of 2000 - 3000 V after arising form a plastic chair. If the first thing they contact is the Faraday cage there is no problem however if the touch a dielectric sample they can charge it up, also if they touch the tip amplifier they can damage it.
Moving up a scale the optical or RH enclosure keeps sample dust free, their mass tends to minimise mechanical disturbances (from the environment) and isolate the experiment from scientists (and visitors) passing through a lab generating air currents and noise. If one works in a quiet corner with a skilled operator then the Faraday cage may be consider redundant, however in a general purpose busy laboratory then either a simple screen or better still an enclosure is well worth employing.