Or they might do a little better and realize that a file extension is actually just a string of characters that don't necessarily mean anything and then search for tools that will open the same extension, and succeed! They then proceed to show their excitement, talk about all the big plans they have for whatever projects they have in mind now that they have access to the data, but then rage when the tool doesn't work and they go off about random things and how coders sux0rz etc. Well of course, the tool definitely did import and export data files with that particular extension, so it should work!
Perhaps windows shouldn't be hiding extensions by default so that people would encounter it when they first touch a computer and go "what is that?"