It is definitely worrying, though perhaps not surprising. Many people who aren't accustomed to dealing with {figures, values, numbers} won't put much time into

It is definitely worrying, though perhaps not surprising. Many people who aren't accustomed to dealing with {figures, values, numbers} won't put much time into doing a back of the envelope calculation, and perhaps didn't put much thought into it. My best guess is that for these folks, "millions" or "billions" simply means "a lot, a really big number that I don't know/can't estimate right now". I don't know how that particular question was phrased, and whether or not you were allowed to answer with "I don't know", or whether that option was presented as one you could answer with.