A guy on bowsite asked about doing this if it be a good idea and if it would help water from getting into the cord and stretching it when wet. I thought id ask the roksliders. I thought it was an interesting question.
I don't see the need other than maybe the Halo type cord on the Hamskea...It will fuzz a little after a lot of shots it seems like.
As far as stretch goes on the regular d-loop style cords....Pre Stretch them before you install them, it makes a difference. I've done it a few ways, tied the cord to something up high and hang weights from it....or tied a loop in each end then hooked the loops on my press fingers and ran the press out longer and stretched the cord under tension over night....Anytime I do that I've never had issues with the cord stretching on me after shooting it some.