I'm not sure where to stand on this. I research diligently, and if I have historic facts, places and actions, I make certain that they are research-accurate. Mind you, that does not mean they are accurate. No one really knows how onions were planted to the north of Rome in the 4th Century. I infer.
And - yes - I walked through Kafka's small house, and looked out his windows, and trolled the outside Lane. And I set a third of my novel there. But - the incident with the lamp - I don't know what his lamp was like. He had to have one, but . . .
And - yes - I painstakingly walked and searched the physical area where three chapters of my current *thriller* happens. But (I confess) I do not know if the shooter could really get away the way I describe. Or if there really is enough room for a helicopter to land there. Or even if a dog can be as well-trained as is Louie.
Mind you, my onion farmers do live in the era of a particular Caesar, and the streets of Rome which they traverse had the dwellings they explored. They meet no motor bikes nor complain of exhaust fumes. Kafka did write his short stories in that small house, but he does not watch TV or ponder the tourists. My thriller characters utilize state-of-the-art communications, but they are not removed from danger via transporter beams or worm holes.
The reality is real enough, but it is not ironclad. It is - dare I say - fiction.