If you get the field using the field key it should return the default value.
The problem isn’t so much the missing value as it is the missing field key reference for the value.
I personally have always coded default values in. The reason, I may add fields in the future, these fields will not have values for existing posts. I can never count the data being there, any number of things could cause the value to not be set. But that’s just me.
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