If your hero is drinking sake in Tokyo you better know which hand he should use to hold the cup; and when he is sunning on the beach at Cape Cod, remember that there won’t be any palm trees-Dean R. Koontz
You can’t get away with faking background information. If you fabricate a lot of facts on a wide variety of subjects, your readers will catch on. I know it’s your story, and it’s fiction, but unless you are writing science fiction that involves creating your own world, you better stick to the facts when it comes to background.
Every time a reader knows that you are faking a bit of background information, your credibility slips a notch. When your credibility slips two, three, or four notches, you will lose that reader.
No one is saying that you have to limit your story to places/things that you know, but if you are going to step into unfamiliar territory, you had better do your homework.
There is so much information available, that there is no reason why you can’t write about any country you never visited, canoe making, basket weaving, the inner workings of an assault rifle, the floor pan for Biltmore house-I think you get the gist of where I’m going with this, but keep in mind that very few reference books are perfect. If you do have to research certain topics, cross-check every piece of information, using two and preferably three sources.
Firsthand knowledge of background information is always more desirable than second hand. There is no better way to learn the sound, texture, smell, and look of a place or thing than when you experience it firsthand, but if you are diligent in your research, you can make your background come alive.