Indeed, but I don't think it's necessarily a bad thing to "leave something in the open" depending on tables. There is nothing inherently wrong with appropriating ideas and making them your own based on familarity. Intent and context matters. If a GM has never met a French person and none of his group ever have or will, who's to be harmed if his depiction of Galt is a cartoonish version of the Revolution, with blood-drinking vampires in charge of the Revolution due to the tasty sweetness of Blue Blood? This Galt will certainly be different from that Galt as seen a French table, but that's great! Certainly, ideas at one table might sounds baroque or outright offensive to people from the other table, but there is no harm as long as the intent isn't to offend, but rather the content is there as a result of differing cultural values and expectations between groups or, more probably simple lack of familiarity (195 countries on Earth, 190 days in a school year, as Umbran said, there is nothing wrong with having only a superficial knowledge of other countries and creating your fantasy elves based on them).