Shows how easy it is... a little rain & white lines... Actually, it looks like he spins before he even touches the white lines. Crazy.
Wow, id say there are a few possibilities: 1. Tyres: Low tread pattern, or slick tyres, or just a crappy make. 2. Alignment: Recently adjusted chain and left the wheel all skewiff. 3. Surface. Large scale diesel spillage over the area. I know that id struggle to lose the rear on my SV even if i dropped a gear and pinned the throttle open on the motorway during torrential rainstorm. There is just not enough power, lol!
I'd guess at a contaminant (oil or diesel) on the road rather than white line slip there. Like you say, seems to go before even touching the line...
Looked to me like he did a shoulder check and dragged the bars slightly whilst aqua planing. All to easy by the looks of it.