Is there statistical evidence to support this?
It may be that some say it's not needed and common sense dictates it must be so, but I've never seen the numerical evidence.
Moreover, horses racing in and out of false patches of overwatered ground isn't exactly risk free to my way of thinking.
The UK racing industry has fallen for the softer is safer line of thinking hook, line and sinker and seems Hell bent on delivering racing surfaces infirm horses can win on and then go to stud and breed (for both codes) more infirm horses.
All of that said, I accept the modern reality and my trio - your moral laydown tricast combo banker - of Intense Raffles (if you have backed anything else that ran in the Bobbyjo, check out the revised weights at Aintree then try not to cry too loudly as it might disturb the neighbours), Stumptown and Iroko will all thrive on the inevitable easy surface.