Is there any detrimental effect to adding the same polyline contours to a surface multiple times?

I'm sure the question would arise as to why a person would want to do that... Here's an example - I have a surface that was initially made from polylines. Then it was added to over here. Then tweaked over there, etc.

Now, it's difficult to determine which are the "new" polyline contours and which ones are already included in the surface without an extensive comparison. So the question is, is there any harm in adding -all- the polylines to the surface again?

Thanks.