How about this instead...
Don't put the macro in the workbook with the data.
Put the macro in a separate workbook (maybe save it as an addin).
Share the data workbook with everyone.
Share the macro workbook with only the people you trust -- and tell them not to
share with anyone else!
Then give the user someway to run the macros--especially if you saved the file
as an addin:
For additions to the worksheet menu bar, I really like the way John Walkenbach
does it in his menumaker workbook:
http://j-walk.com/ss/excel/tips/tip53.htm
Here's how I do it when I want a toolbar:
http://www.contextures.com/xlToolbar02.html
(from Debra Dalgleish's site)
In xl2007, those toolbars and menu modifications will show up under the addins.
And if you use xl2007:
If you want to learn about modifying the ribbon, you can start at Ron de Bruin's
site:
http://www.rondebruin.nl/ribbon.htm
http://www.rondebruin.nl/qat.htm -- For macros for all workbooks (saved as an
addin)
or
http://www.rondebruin.nl/2007addin.htm