I'm not surprised. At the time, almost every question every week in Parade magazine was just pulp. Questions of the type "what's the world's smartest woman's favorite color?". You could take anybody off the street and get the same answers. Parade magazine was a gossip magazine.
Furthermore, at the time she wasn't listed in the current Guinness Book so anybody that looked it up would see the column as a fraud unless they checked a specific old edition. Claiming somebody "is listed" when they had been listed, for one year many years ago, is a lie.
So there were a lot of readers who thought of the column as a joke. If you open 99 doors that are full of mindless drivel, what are the odds the 100 is the one that has something interesting? This is why so many people were fooled by it.
> If you open 99 doors that are full of mindless drivel, what are the odds the 100 is the one that has something interesting? This is why so many people were fooled by it.
So they thought "ha, this is foolishly wrong, I'll write in and tell them that—of course, without doing the 5 minute math check to make sure, first!"