Not having the DataFinder index anything except NI's folders by default on install would be extremely convenient. Optionally, this could also be a setting chosen on install.
Each of our users who installs the application immediately has every MS Excel file from their 'My Documents' folder indexed, which wouldn't really hurt anything except that most of these MS Excel files aren't true 'data' files. In my experience, most Excel files rarely store anything as simple as what could be stored in text-tab delimited format, so aren't easily or usefully indexed, so seems to confuse the DataFinder as it is unable to close them automatically once opened.
The results is dozens to hundreds of Excel.exe processes running in the background, until the machine runs out of memory or files, so we have had to make a point to disable all datafinder indexing on each and every install. We've scripted this process into our standard configuration, but if the user doesn't contact us right away, they suffer greatly from performance issues and blame DIAdem (rightly so).
I suspect that anyone who wants to use the DataFinder would want to do some manual configuration to specific folders, dataplugins, times of day to index, etc. which would make requiring setup perfectly acceptable to users who want to use it (and not waste resources for those that don't).
-Josh
see Brad's comment