Regardless of whether or not Mr Toyota thinks a hose should be there, I would install one. You probably will never see any fluid coming out the vent, but I think it needs some protection to keep out dirt.
Put on a piece of generic neoprene vacuum hose of the correct diameter and route it securely towards the bottom of the engine compartment.
BTW - how are you supposed to check the coolant level? Hot or cold? If cold then your tank is low.....
Thanks, that is just a shadow, it actually is all the way to the top, may be needing that vent tube, and if some were to come out it will run down that little "valley" and then spill right on a bunch of stuff. I think I will try to find a hose for that.
I know Toyota has come out and admitted they might of went to far in their recent cost cutting measures. Maybe the overflow hose was deemed a great way to save a buck. (BTW the article where toyota admits this is the C&D highland first drive)
My RAV has no hose and my Mazdaspeed Miata has a right angle hose about 2 inches long that allows any overfill to drip about in the same place it would without the hose. Other than the cars rolling over, how could the fluid leak out? The containers are above the radiator and fluid can expand just so much before it blows apart something. Wouldn't the radiator cap or a hose leak first or would it send the excess pressure to the overfill tank? I haven't seen a car yet with a blown overfill tank but maybe it happens.