What is to guarantee that the third column is always the column you think it should be?
What do you mean? Why wouldn't it? Unless I manually move,delete or add a column (which I wouldn't...as my engine handles all the reindexing from adding/removing columns), then I don't understand how that would happen.
Also, without ranting on in a long explanation, my engine sends this data to several subservers that send the data to clients, so including the column names would really hinder my currently comfortable bandwidth usage.
There's several other things it would complicate if this is not possible.