Oh, I've never noticed a problem, maybe it's just something girls do when they're with strov to try to put him off by making it too much of a faff.
Well, it's not just that, is it? I mean isn't awkward for them when they want to go and wee? I'd ask the Memsahib but she only wears tights!!
Wouldn't have thought so, they can still get them half way down their thighs so that should give them enough movement to do what they need to do.