We shouldn't be able to make sheetnames bigger then 31 characters.

[jappeace]

The reason is that excell claims the worksheet "may contain a virus" if it detects this. Excell validator explain this:

File: xlsx/avy.xlsx
Error: The attribute 'name' has invalid value 'Gross written premium (calendar years)'. The actual length is greater than the MaxLength value. The length must be smaller than or equal to 31.
ContentType: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet.main+xml
XPath: /x:workbook[1]/x:sheets[1]/x:sheet[1]