Underscore vs dash in excel sheet names

this could be funny, if it were not a big issue in the elaboration of a questionnaire.
As I previously mentioned I'm working on building a DB for DG-Infso (EU) from some thousands of answers made by project leaders, collected via Excel.
The bad thing was that apparently many people had changed some of the worksheets, changing dashes (-) to underscores (_) (that was like publications-papers becoming publications_papers).

Even if I understand that for somebody's taste underscore may look nicer than a sign that resemble a minus (so attracting negativity) I did not feel like dozens of people would be taking the effort of manual substitutions just to avoid bad karma.

So I suspected "maybe they are mac users?" (you know mac users are more estetic-oriented...) until I found this post on OPENOFFICE.ORG explaining how openoffice calc changes dashes to underscore in worksheets names.

So cool...