My husband has used a mandoline once in his life, not counting the time he put one away for me. Both times he has cut himself. This time it was bad enough for a late evening taxi ride to an urgent care center. He's fine, no stitches thanks to my kick ass gauze and tape skills and his constant pressure. It was sealed by the time he was seen, but he still got a tetanus shot just in case. The tip of the thumb on the dominant hand is a bad place for a deep cut. The doc sent him home with a bandaids on his thumb, a splint to protect it, and a sling to keep it elevated and not used. All for a cut on the thumb. I laughed at him and the photo of this get-up is now his profile pic. Silly man.
But seriously, use the hand guard. Don't be an idiot like my husband.
Edited for spelling.