Years ago when I was still instructing, I had many events in which BFR clients would grab for the gear lever before they had a positive rate of climb and a couple hundred feet of altitude. Whenever I saw that, we'd go around and land, and we'd have a discussion about it. I don't think any of them really had given it much thought, just automatically included it in their post-rotation procedures. I don't recall any who actually pulled the lever up while still on the ground, but several were darned close.
Good bet that the pilot had the lever up early--and it might have been up when he first cranked up, due to a sloppy pre-flight. To counter that, my personal method was before I'd do the exterior part of the pre-flight, I'd reach in and make sure the lever was down as the very first step, before touching anything else.
Cary