from what I know of the physics (small) and my discussions and research on the subject (somewhat larger) - There is a pretty minor improvment in performance once the width at the trailing edge gets below a certain size -
For most of us - Olympic contenders excepted - the increased performance is far outweighed by the risk of damage and the difficulty of repair. Remember - those foils are not even fiberglass, they are foam.
Ok I will give you that it is sanded but sharp? Most foils I have dealt with are not straight when you get them. Some sanding/heating/clamping etc is required to make them right. I am sure you are aware of this. Being "in the buisness"
I am not affraid of outside the box thinking but thats not proof. I do like her set up for the start. And her Cunningham rigging. As well her apparent upgrade of the Vang block at the boom. She is not using a clewstrap but an old school peice of spectra.
There are a few other interesting things to pick out from these pics concerning her pref for rigging - look at the same pics in row 4 (worth waiting for the larger pics to download) and see how many things you can come up with that aren't stock as far as the standard pro package goes. There's one in particular that has me thinking.
I believe Rob's point in the first picture is that if she were only intending to head up, then the tiller would NOT be pulled over to windward as much as it is. Check what's happenening with the turbulent flow off the rudder, if anything the rudder is driving the stern to windward and the bow down, ie heading down... Next look at her forward hand - on the boom, keeping the boom out. That helps keep the boat from heading up as well.
The rule says you can heal to help steering. Race committees and other racers don't bother much to check at the start to see if you're in fact heading up or just rolling, because everyone does that at the start. She appears to have just started to lean over, so is heading the boat down so she can head up when she flattens, or maby some other reason above all of us. The point is, it's not a violation of rule 42, which was the original question.