'How do you know?'
Limahong, I would like to answer your question, I use a three circle system that helps to add dimension to spirits. If a person is initiated into the world of spirits, then to show respect the week spirits make a effort to move more slow to be seen and the more powerful spirits can be visible whenever they want to. Marbiehead, was correct about 'spirits getting naughty sometimes'.
In my experience people initiated into the world of spirits who have accomplished creating their own fully functional energy body can choose to send their energy body out to do mischief.
Wild Hunt:
'practitioners of various forms of magic, joined in it voluntarily, as an intangible part of them (a “soul,” if you like) flew with the cavalcade while their bodies lay in their beds as if sleeping normally.' http://norse-mythology.org/the-wild-hunt/
