The Greer shills. When you meet flesh and blood aliens in his seances, cough cough I mean CE-5s, I'll believe it.
Until then you are dealing with non-corporal spiritual phenomena. Don't let them in, or they will take their pound of flesh from you.
Fair warning anons.
Real aliens don't need to participate in mumbo jumbo and freak light shows. Discarnate beings on the other hand do.