Oh, they can totally be tell apart (Well, *I* can. Actually the actresses aren't even sisters), it's just that I 1)have troubles remembering their names 2)am SO interested in them that I never bothered remembering which one is doing what.
Ok, actually I would bet for Lavender for HP6 because I think the other one's name is shorter and this one seem to be the right length, but... (and then I don't know why they picked the cutest one to play the other sister, considering we'll have to see her that much in two films. Hopefully it's because the less cute one can act better? Hopefully?
EDIT: Nah, I thought about it before hitting "Post Comment". THey started shooting before the release of HP6. That explains it. She probably doesn't play any better. Oh gosh, oh gosh.... *eg*