If they just mean a cover-up ti wear by the pool, then thats what they should say, they have to be made of polyester to be sheer and see through (clearly the intended style) otherwise they would have to sell silk for much more money. I have a couple of tops that are floaty and sheer ( and one is silk, the other is polyester) which I got from Bay Trading for a fiver before it closed, and the polyester one was from New Look and cost more! I dont think the TRUE kaftans from the 60's would do so well on Q... Bit of an "acquired" taste. Great for wearing round the house with nothing underneath though... imagine them saying THAT on air!
Slightly off topic I noticed Michelle Hope was selling some stretch trousers yesterday which she said were 95% cotton and 5% elastane for the stretch.... not bad, maybe she's listening to what people say after all.