If you watch a lot of Samia Gamal's old movie clips, she wears completely sheer skirts with dance lollies(briefs) in the same color as the costume, and you can see them. I should post a link.
Okay here are the only 2 youtube's I could find w/Samia wearing her sheer stuff. There are more clips of here w/ full sheer skirt and dance briefs, (I have them) but I couldn't find them on youtube.
sheer harem pants:
http://www.youtube.com/watch?v=_qvT6LdG7Is
sheer ballroom skirt:
http://www.youtube.com/watch?v=Vasa6vIy1uA
It just depends how you wear them.
Think of jazz where your legs are visible a lot of the time. I don't think it's offensive to see full leg through sheer skirts. Just own it.