I work in healthcare and by far the biggest production issues we've ever run into are people who run Excel spreadsheets through our file processing where the leading zero's have been removed from patient identifiers because that's Excel's default behavior and you CANNOT TURN IT OFF!
EDIT: I have no idea who downvoted my post because what I said is 100% true. We have to tell customers to stop opening CSVs in Excel and then uploading them to us because what they upload could be missing critical data. Excel interprets a number and then formats it as a number, but in healthcare, 10 digit numbers are really strings. Unless your IT team has created an Excel extension and had it preloaded onto your local copy, Excel will remove leading zeros and there isn't a way to get them back if you save/overwrite.
EDIT: I have no idea who downvoted my post because what I said is 100% true. We have to tell customers to stop opening CSVs in Excel and then uploading them to us because what they upload could be missing critical data. Excel interprets a number and then formats it as a number, but in healthcare, 10 digit numbers are really strings. Unless your IT team has created an Excel extension and had it preloaded onto your local copy, Excel will remove leading zeros and there isn't a way to get them back if you save/overwrite.