Jerry
I use a cut off piece of copper pipe for SpO2 sensor tests and a metal can that I wrap the cuff around for NBP testing.
I also take an electrical connection to the end of a fluid filled syringe or infusion set fitted to a pump for pump electrical test.
I can't give you any reference for the above practices. My peculiarities are referenced to my own head !
However I think the type tests in the IEC standard are where people get the idea of putting foil onto equipment enclosures or standing Class 2 items on a metal plate.
With a modern automated safety tester the additional time per unit taken for these precautions is minimal. The point of a safety test is in fact to show something is safe. Having no failures isn't a waste of time, it shows the equipment is safe! In the unlikely event of someone suffering imagined "burning" or genuine shock it can be shown that up to the point of the last test the unit was safe and it's history is consistently good.

Geoff
I don't think you should be spending your valuable time suggesting technicians who are zealous have "spare time". Risk assessment takes time in itself and places a far higher burden of liability upon a technician than does covering all the bases in a simple and practical manner.

Marc