addition to OP'S suggestions,sorting names alphabetically would also help Bounty Managers to identify double entries easily,the BM's just need to check the timestamp to determine who is the original and who is the fraud.Another way to prevent those "effort-grabbers" from their fraudulent work is through google form system of reporting.all reported task will not be available to the public and only the BM and his team would have access to the submitted reports.this way,cheaters won't have any chances making a duplicate report and stop doing crazy things like these that sometimes have bad effect to other good bounty hunters
Now I am beginning to understand why some spreadsheets are not available to the public. However, as a bounty hunter, it is so hard to trust someone who does not show the spreadsheet especially the updating of the stakes in a weekly basis. I am meticulous to the bounty managers of the bounty campaigns that I join and I always make sure that those bounty managers are diligent enough to update the stakes on a regular basis (especially on signature campaigns)