Yes, I have been.
It is not an experience, I would like to go through again.
Sat in a darkened room, with three other people, we were subjected to the most frightening sights and sounds imaginable.
Spirit like figures, about the size of a football, appeared from nowhere and were circling around us, making screaming noises, while at the same time, glancing by our faces, as though they were trying to attack.
By this time, everyone was overcome with fear and we were calling out, for them to leave us alone.
I think it only lasted about five minutes, but it seemed like an eternity.
Afterwards, the medium herself looked a bit shaken and apologised, as she had never seen so much spirit activity, in one session.