This conversation has been merged. Please reference the main conversation: Lightroom: Delete Images on Card after Import
Simply copying files from the card to the computer gets a bit confusing. I shoot many hundreds of exposures in a day, and having all these files left on the card after import can present its own problems.
I understand that the idea behind preventing Lightroom from deleting files is to protect them, but I find that having thousands of files left on the card could be more dangerous since there's no quick way to find what's been imported!