Having deleted a specific mailing list with 2500 entries and losing 100 of the rebuilt list on a separte key entry error, I don't know whether my problem is applicable only to me or whether others have made the same error. When working on a mailing list, I occasionally find an entry that is no longer applicable (retired, left industry, promotion puts them outside our customer profile etc). In some cases we delete the entry from our database. On moderately large databases, this becomes a speed game and when I hit delete, I expect that I am deleting only that specific contact. Generally, the "delete lookup" button is not active. However, on at least two occasions (as noted above) the button was active and I moved so fast that I deleted an entire lookup instead of the specific entry. I didn't realize my error until it was too late. On the first dump, I lost the entire mailing list of 2,500. I was able to rebuild it because I had exported it as an Excel file for the mailing house (though I lost all the links to activity, e-mails, etc). In the second mistake, I pulled the plug on the computer and stopped the dump after only 100 names were lost.
It seems to me that there are two ways to prevent my particular brand of stupidity. One way, mentioned in another post, is to have a trash box that requires a second deletion before entries are truly wiped out. Alternatively, the "Delete Contact" button could open with only one option - "Delete Contact". If you want to delete the entire lookup, you would need to use a separate drop down that might be called "Delete Lookup".