It's amazing how much can change in 10 years. By the 1920's, many women went out and about without hats (i.e. flappers). It's surprising what differences a world war can produce. I don't think these people really considered Lois a prostitute but more likely an oddity or a loose woman. Women wore hats to keep their skin unblemished from the sun and as pale as can be. She probably doesn't realize how scandalous it was during that era it would have been to be seen at young man's rooms. (More so, than not wearing a hat.) Yes, wearing an evening dress during the daytime will get people to look at your twice nowadays as well.
I like that Lois is considering all the ramifications of what someone from the future might have in the past and the difficulties she will encounter should she not make it back into the future.
He sighed. “I spoke to a medium once. She knew things that….she couldn’t know. She told me that I would meet a woman who would end my life as I know it.”
Lois froze. “And you thought that women might be me?”
He flushed again. “There were things she told me that led me to think so.”
Hmmm. I wonder what the psychic said. Did she mention something generic about the age Clark would be when he met his mysterious woman? Did mention that they would meet by a lake? Or did she say something more specific about the most attractive woman he had ever seen or something about how Clark would physically react to seeing her, instantly falling in love with her? I think this might be the case, since he "flushed" when he mentioned the incident. If Clark mentioned what the medium said to Robinson, then it might explain why he's so overprotective of his actor. Even back in the 1910's actors were known for their wild lifestyles, and being that Clark is male... more generally acceptable lifestyle.
I could see why the medium's words would make Clark nervous, too. He thinks Lois will be the person who carts him off to be dissected like a frog, instead of teaching him the wonders he can do with his powers.