Ritual disclaimer: nobody gets through a long writing career without some mistakes. You will sometimes trust the wrong research source (even if it’s someone who should have the knowledge you’re looking for–say a fire department veteran you’ve asked about a procedural point in managing a multi-alarm fire…and no, this isn’t a problem I’ve had.) No writer knows everything, and every writer must, at some point, trust a map, or a reference book, or a person who seems to have first-hand knowledge.
But there’s a huge difference between occasionally trusting the wrong source and not looking something up at all. Writers should look things up in the best source they can find or beg/borrow/get via Interlibrary Loan before they plan a book or a chapter–and should let the facts dictate how the story goes, rather than ignoring the facts because they already have a fantasy-version in mind.