I was surprised at the polling results. People would rather a human in the basement than roaches? I mean an infestation would be pretty rough but I have dealt with them before and, although they're hard to get rid of, they're pretty harmless. Just very annoying and gross.
Considering the fact that the human isn't specified, I am taking the initiative to say that the human is someone I do not know. Now, humans are unpredictable, especially strangers. So, seeing someone in my house, in which I had no knowledge of them being there, would be genuinely terrifying. The person could be armed and have the intent to kill. I am a 154 tall female with no upper body strength. If it were to come down to a fight, there would be small chance I would win. If they were harmless, there would have to be a whole thing about why they're in my house and calling the police and having to deal with squatters rights. ('murica baby) Just a lot of hassle.
On the flip side, I could just call an exterminator.