I've come back to report on the Icon incontinence knickers. I'm 51, post-menopausal, sometimes "tinkle" a bit (that's their word for it in their advertising!) There follows TMI, but that's what mumsnet is for: 
They are really good, I like them. I give them a gold star 
They look like normal pants so I was happy to be changing into them in the communal changing room and not faffing about with pads. They hold up to 5 teaspoons of urine at a time... the gusset is made up of several thin layers of special material which seems to work by wicking the liquid away quickly and the material is a new type that dries very fast. So the gusset is slightly thicker than the rest of it (quite like normal knickers!) They arrived in 5 days from the US. Quite expensive, but I've stopped buying the pads from Tesco now. And it feels great to NOT wear a pad EVERY day. I'm convinced the fact of not wearing /sitting on a bulky and lumpy pad has actually helped me wee a bit less.
As for Thinx, I bought 3 pairs for my daughter, who is grossed and weirded out. She hadn't used them when I asked her and says she can't imagine having to wash them, ick. I suppose as we get older we are less grossed out by it all but I hadn't thought of this teen aspect. They do say on their advertising that the blood disappears, which I can believe, as the water content would evaporate away with the special wicking material. I read advice to pick off any solidified clots with toilet paper when you go to the toilet. If I still needed sanpro I would use them in a flash and certainly at night when more accidents occur. What's to lose? I think they must work as the icon ones are great with little gushes, and the Thinx ones would be more for a constant dribble.
The special material in them is black. This can't be seen from the outside (I bought blue, nude and black ones). Now I've washed them probably 20 times and they're still as good as new, I like the black colour - I suppose they might be stained, but it certainly doesn't show.
Has anyone any actual Thinx experience? If DD uses hers and can bring herself to tell me about it, I'll report back again. 