It depends on the temp of the fuel in the wing, the temp of the fuel in the truck and whether or not the wing had frost/ice on it.
If the fuel in the wing is below 0°C and remains below 0°C after refuelling, any frost/ice that was previously on the wing isn't going to disappear that quickly even with +8°C OAT, unless removed "manually".
Basically "clean wing policy" applies. You may accept a thin layer of frost on the underside of the wing in certain areas.
Some okes just apply "procedure X" to all situations without adapting their mindset to the given conditions.
Tankering can become expensive when additional costs such as deicing come into play because of misjudgement.
But if in doubt, you can be rest assured that your wing was "clean" after deicing.
edit:
Yes, as pointed out below, the dew point temp is significant as well.