Is this based on real accident statistics?
If you ride motorcycle without gloves and jacket and crash you will have much more severe injuries to care about much more certainly. So I would doubt wearing a watch is a significant risk factor.
Also, as a developer, I don't care as much about losing functionality in my lower body. My wrists, hands and brains however are how I make my money. Even though I have full disability insurance, I still would much rather keep working than sit at home.