Yes, having both wing tanks feeding out of all four corners will keep fuel flowing to the engine in normal conditions, but so will a headered Cub. You could skid a headerless Cub in one direction long enough for the fuel to cross feed to the low wing and vent out the cap. Is this really nessessary?
It is fixing a problem that in the real world, doesn't exist. The headered system has been around a long time, operating with few problems, other than a few old persistant wives tales about how it works.
I've crossed up a Super Cub in some very interesting conditions, and it always feeds. Worst condition, feeding right tank, right tank low on fuel, skidding steep right turn. You need to hold this condition for about 3 minutes before the engine quites. If there is some condition you think will make a headered tank Cub quite any faster, let me know, and I'll try it out. I know that with my system, if I switch tanks, the engine will restart almost instantly.
However, I can't say that about the headerless system, and in the same condition, the headerless system may not even make it the 3 minutes. Yes Crash, I believe you can easily starve the engine with fuel in the tanks. Here's how....
For the sake of arguement, lets hold the headerless Cub up to the same scrutiny. Take your headerless Cub with both, or at least the left tank low on fuel, put it into the same steep skidding (top rudder) right turn and hold it there. All the fuel that in feeding the engine from the left tank is ALSO feeding through those big 3/8 lines, T's and vents into the right tank. Depending on how much fuel was in the left tank, at some point the last drop is going to cross feed into the right tank, and guess what?, the engine quites. Now you can't just switch tanks to a header that is full of fuel to restart the engine because you don't have any headers. All you can do is level the wings and wait for the fuel to start flowing from the right tank, through all those lines, all the way around the cabin, hope like hell it doesn't air lock somewhere, and restart the engine.
With the headered Cub, I know how long I have before it quites, and I know that when it does, I can get it back under power almost instantly.
With the headerless Cub, I know it's going to quit, but have no idea when, and when it does, I have no idea how long it will take to restart. And if it doesn't start quick enough and I crash, I have all those extra fuel lines wrapped around me that can break and soak me with fuel.
So what is safer? The headerless system tries to fix a problem that really isn't a problem, and the reality is that it creates a whole bunch of new problems.