And maybe it is the new normal...
although the applicable software list is ancient
Software: ArcGIS-ArcEditor 9.3.1, 9.3, 9.2, 9.1, 9.0, 10 ArcGIS-ArcInfo 9.3.1, 9.3, 9.2, 9.1, 10 ArcGIS-ArcView 9.3.1, 9.3, 9.2, 9.1, 9.0, 10
From your link
Do not start field or table names with an underscore or a number.