Good points on the night time variances, forgot to mention them. There are countless examples of PWC accidents all over the country every year, no need for more at night. Heck, there are many PWC collisions with docks and other boats each year in broad daylight
As always, there are accidents that are just plain accidents, can't really eliminate them. I would say most accidents are the result of inattention, poor skills, alcohol, shear stupidity and thrill seekers, and I'm sure somewhere down on that list is someone focused on their little screen.
But the fact remains that all over the country we have bass boats doing well north of 70 and they seem to be fine for the most part, and people running over boats and hitting islands that are doing less than 30. Seems to me you need to go fast to be safe.