As an avid reader, I have run across the word "kidnapped" (or a variant) hundreds or maybe even thousands of times throughout my life. After all, I read a lot of crime fiction, where that's a popular plot point. I also read and enjoyed Scottish-born author Robert Louis Stevenson's famous novel "Kidnapped" when I was a child and that probably went a long way toward cementing the more common spelling in my brain and making any alternative spelling pop out from the page. In spite of doing more reading than a lot of folks I know, however, I can't recall definitely ever seeing the word spelled "kidnaped" until this discussion. I decided a little research was in order!
A quick look at a few online dictionaries (and a corroborating test in Microsoft Word) shows EmP is technically correct. The percentage of authoritative sources that use the single-P spelling may be small, but it's still very real. Though the spelling is generally not in favor, the word
can be spelled with just the single "P" if one has an accommodating copy editor. I have to imagine there are examples of this less common spelling in literature or "popular" use to account for that, though as noted, I've never seen one. We might be in the middle of a period of transition, since word definitions and their spelling do evolve.
Someone might reasonably suggest "Well, perhaps this is the case of a European spelling versus an English one." Is that what happened here? Additional searching suggests European literature also spells it with the second "P" and this point is even addressed by documentation I found
from a UK grammar/spelling authority. I had wondered if European writers at one point spelled it with the single "P" and Americans dropped that habit due to evolving grammatical norms, but just the opposite appears to be true. This
interesting discussion, also on a UK site, referenced documentation showing the word was spelled "kidnapped" when it originated in England in the 1680s. Apparently, the word at the time of its origin referred to people taking children away from their parents to carry them off to the colonies. I failed in my attempt to find any UK source that spells it with the single "p," but I did find a few American dictionaries that do, which leads me to wonder if the single-P spelling might actually be an American quirk. We've certainly changed English words around before, so we could be guilty of it here too.
Where acceptance of that less common spelling comes from appears destined to remain a mystery, but it does look like EmP can get away with it if he likes. Many alert readers will assume he's wrong, but as it so happens, they'll be the ones who are wrong.
"Too often we enjoy the comfort of opinion without the discomfort of thought." - John F. Kennedy on reality
"What if everything you see is more than what you see--the person next to you is a warrior and the space that appears empty is a secret door to another world? What if something appears that shouldn't? You either dismiss it, or you accept that there is much more to the world than you think. Perhaps it really is a doorway, and if you choose to go inside, you'll find many unexpected things." - Shigeru Miyamoto on secret doors to another world