Help with shared worksheet protection....

I would be inclined to have it readonly. (File, Info, Protect Workbook, Always Open Read-Only). People can choose to save it but they have to consciously decide to do so. 

If that won't work you could use vba code that clears the cells that people fill in and then save the workbook again every time someone closes the workbook. 

Something like this:

Private Sub Workbook_BeforeClose(Cancel As Boolean)
    Worksheets("Sheet1").Range("B3:B4").ClearContents
    ActiveWorkbook.Save
End Sub

That way you know the relevant cells are always empty whenever the next person opens the workbook.