I guess I'm amazed that it is "known by the authorities" when someone is "going by" the second rather than the first name on their birth certificate. How would "the authorities" know such information?
It certainly makes for a somewhat more accurate list in terms of what names are actually being heard in the culture. I have often thought that boys' name lists for English speaking countries would look less "conservative" if we could know which boys had a first name from their father or grandfather but were really being called by a middle name. My nephew-in-law, for instance, is named Thomas Brian
but has always been addressed as "Brian
". For an American his age (30), Brian
is actually the newly fashionable name, but in official records he looks like a more conservative "Thomas
". But we normally have no way in the USA to discover such cases in the general government data. :)