People have been wearing dredlocks for centuries and if you take care of them then they can look very nice. I don't particularly care for cornrolls on men (I tried it once, didn't like it) but I don't see any problem with them on women.
It's quite popular for white women vacationing in the islands to get this done while down there, but speaking from experience, most white women shouldn't attempt it. The woman in the pic above looks ok, but most of us look like mangy dogs with 'rows - anglo scalps are not the prettiest. Me? I think they should outlaw white girls with cornrows but let everybody else who can pull it off in!;-)