I don't call it "spidey sense" but I live my life based on that gut feeling. And, if I'm into a family genealogy I trust that gut when something just doesn't feel right.
I also don't like the excuse, "people were illiterate back then". That's not true. Many spelling differences came about because 1) there were strange attempts to Anglicize a foreign name, 2) Webster hadn't written his dictionary yet so spelling wasn't standardized, you spelled it the way you spoke it.
Sure, there were uneducated people in the "old days" just like there are uneducated people today. But, it wasn't the norm. Even without a school, parents taught their children to read and write and do basic math.