Well its not lame if your haunt is one with a story to tell, but if not and there arent multiple GOOD places the actor could hide or something then yeah its pretty lame. But what scares guests the most ((From My experience that is)) is the fear of the unknown. I once held a haunt and i had this huge room, it was just one dim light in the center. I had no actors in there. Just one guy banging on pots and pans in a dark corner. I got many comments as people were leaving that, "That big room with that one light was terrifieng!". So im sure you could play of that factor.