What is the risk of icing with water / moisture on wings prior to takeoff? If a plane without any deicing equipment has water moisture on the wings (say, from sitting overnight) and that plane is then flown to an altitude which will have temperatures below freezing, what is the risk of that initial moisture causing icing concerns? 

For the sake of hard examples:


Plane: Piper Cherokee 140
Air temperature on ground: 40°F (4°C)
Air temperature at cruise altitude (3500ft): 28°F (-2°C)
No visible moisture in the air, the only moisture is the moisture on the wings prior to takeoff.


Questions:


Will this be a problem?
If it is a problem, what is the best course of action to protect against the icing concern?
Taking off with wet wings is not a problem, the airflow is going to blow the water off long before it reaches the freezing point. There's no concerns here. 

Given the scenario what I would be concerned about would be ice elsewhere on the airframe. 40°F (4°C) could mean that the aircraft was frozen overnight, and there could be ice left over where the sun didn't melt it off. That kind of ice wouldn't necessarily impact the airflow on the wing, but it would make the airplane heavier and therefore impact performance. A simple visual check on the walk-around will confirm this. If there is ice left then deal with it even if it's not on the wing or tail, if it's just wet then get in and fly.