Yeah...really not a big concern here.  I've never needed one to the point that I would drill a hole into my cedar stripper or kevlar for that matter.  I do have a brass loop mounted on the deck of the bow and stearn where I attach a rope if and when needed.  

My concern about attaching a line near the water line, is that your water line changes with different conditions and weight, etc.  I know there have been several times, especially in rough conditions that the bow of my boat is breaking and cutting waves, unfortunately sometimes over the bow.  That being said, I want my boat to be as clean and efficient as possible when cutting through the water. If I were to  do this I wouldn't do it more than a couple inches below the gunnel.  

But, "differnent strokes for different folks"  Good luck, I hope it works for your desired purpose.