I recently had an issue with a form where a calculation that used a field that was set to Null gave an unintended answer for a critical field and I didn't catch the error until several hundred surveys were submitted (the curse of a tight time frame to finish the form and limited beta testing). Fortunately I was able to pull the SQLite database off of all the collection devices and get the Null values and recalculate the filed in the database. The Sent Surveys provides a great back up if something goes wrong, it would be a nice enhancement to allow the form manager to disable or password protect the "empty" button in the Sent surveys box/tab (or have a warning window pop up) to ensure users don't intentionally or unintentionally delete all of their sent surveys.
