Indeed, most road accidents and fatalities involve motorcycles of one form or another. Traffic rules do exist but more as a rough guideline. Road blocks are held when the traffic police needs a bonus or for funding for a social event. Fines will usually be 200 Baht (AUD7.5) paid on the spot with no receipt. Sidesaddle pillion riders are common and, what you don't see on the video, so are two to three passengers plus the driver on a scooter.
As for myself, I've done several advanced driver courses in the past which stood me to good stead. I've learned to look three times or more before making a move. I avoid riding at night (it seems lights are also optional). I never ride without at least a helmet. Around the village, I'll sometimes go without gloves but it's rare. And never wear shorts or flip-flops as you would see often.
Thailand has some of the best rides but you better be prepared before taking to the road.