Plastic Covers are a No No!
As noted, the lifeline covering is applied as an extrusion (hot) and it bonds with the strands to make a covering that is strong and takes abuse well. Applying split plastic/Teflon covers over the lifelines is a cheap and unsafe practice. The covers you find in all the marine supply houses are sold as shroud covers and are intended to reduce the friction where sails/sheets pass across them (they also look pretty). If someone grabs the lifeline with plastic covers, they may find themselves clutching a length of plastic when they hit the deck or worse yet, when they hit the drink. If you have some of the plastic covers on your shrouds, do a few simulated falls while grabbing the plastic covered area. I think you will see what I mean. IMHO, SAFE is Better, do it right and replace the lifelines (that's what I'm doing this year).
