When I already have 20+ feet of plastic rope tying off the end of
a wire antenna, what additional benefit is a couple more inches
of plastic going to make?
So I just tie the rope to the end of the wire. Never had a problem
at 100W.
That assumes, of course, that your rope is an insulator, but there
are so many options these days in nylon, polyester, Dyneema,
Kevlar, etc., that that shouldn't be an issue. Some of the braided
fishing lines are excellent, and at the moment my doublet is strung
up with black "tactical micro cord", which is almost impossible to
see from a distance. (The wire is about #26 with a brown/green
stripe, and is difficult to see unless you get the sun on it just right.
Or when you get frost on it...)