Though Ol' Myrt here is sure there can be errors with any indexing project, last night's Second Life discussion of naturalization papers brought the following mistake to light.
Yesterday afternoon, I found this card by going to Footnote.com, then Naturalizations, then choosing NY Eastern July 1865 -Sep 1906 collection. I then selected the Index rather than petitions. I then chose Yozzo, and then Giacomo.
Notice that this index card for Giacomo Yozzo is listed as arriving in 1848 (per circle above on Footnote.com "you are viewing: dialog box. Yet the date of arrival May 21 1891 would have most likely precluded a naturalization date in 1848, since there were residency requirements. Note the Date of Naturalization of Aug 1 1898 where the 9 in 1898 could have been construed to be 1848.
When only place, year and name are the fields indexed, we're not able to locate this document if anticipating naturalization at the end of the 19th century. Fortunately, Yozzo is an uncommon name, and it didn't take much to review this older index card, as part of a diligent search.
I am not faulting Footnote. No one indexer is perfect. Even with double, blind data entry
(such as at FamilySearchIndexing.org) handwriting can be challenging to decipher.
Happy family tree climbing!
Your friend in genealogy.