An isolated spot, somewhere you would be surprised to see another person. The ideal location is a cave but in the case of heavy rainfall or other extreme conditions capable of inducing rock fall, or in the case that your chosen cave is occupied, a location such as an underground car park or enclosed viaduct can be substituted.
an alarm was triggered as we squeezed through the broken fence to
access the site. The fence was replaced and held up by a commercial
waste bin. Subsequent arrivals each set off the alarm and curtains
twitched as the fence was rebroken and rereplaced a further 5 times.