password option is a good one,
however if you add it to right click would you set it so they have to enter a password each time?
if so something like
Private Sub Workbook_SheetBeforeRightClick(ByVal Sh As Object, ByVal Target As Range, Cancel As Boolean)
Pass = InputBox("Enter Password", "Promt")
If Pass <> "password" Then Cancel = True
will work. however unless you hide the menu bar and disable the ctrl+c, ctrl+v etc keys then this will be easy to workaround