I don't know what exactly you mean by an unseen presence but if it is the auras of humans and angels they are present everywhere. What I really felt as almost tangible in air was the animosity of the local JWs for an anointed who was at times critical of the FDS.
Nope never have ......but I am afraid to take a bethel tour! I have this "goosebumps" fear of being confronted by a demon like in "The Devils Advocate".