Are there accident reports suggesting that carb ice was a risk factor at any temperature, on a clear blue day, when you can see forever?
Not at any temperature, you are safer when it is cold or very very hot.
It's also type dependent in my experience, as in airframe/engine combination.
Thus in a PA28 you'd be unlucky, in your trusty mount you'd have to be a little more careful in high humidity conditions.
It may also be location dependent, e.g. my local field
35007KT 310V030 9999 FEW015 14/11 Q1017 NOSIG, looking out of the window, you can see forever, but it is quite humid.
No big deal if you regularly check the carb heat.