For what it's worth, back in the mid 80's, I was acting the part of the casualty for a 78 Sqn Seaking mountain sits training exercise on Pleasant Peak.
"Get somewhere really inaccesible" was the brief "Make it difficult for the winchman".
I did as I was told and lay under a rocky outcrop out of sight. When eventually 'rescued', I discovered my immersion suit legs were covered in a black oily gunge.
Going back to the outcrop, sure enough, there weeping out of the rock was the said gunge. For some reason the theme tune to The Beverly Hillbillies came to mind.
Make of it what you will.