While I was at the Joe Nall Flyin and as I was taking pictures, which can be seen at (not selling anything, I just enjoy photography and airplanes) ......

http://webpages.charter.net/benlanterman/Index.html

and

http://public.fotki.com/benlanterman/

I noticed that the surfaces in the aerobatic airplanes were drooping. I have to admit total ignorance about the modern digital servo, I can't afford them. I asked the second guy I took a photo of if he could move the elevators to align with the horizontal tail, it lookes better on the picture. He said no and demonstrated that the weight of the tail and the low power off friction of the servo would cause them to droop to full deflection in a couple of seconds. I was impressed at the time with the friction free setup and only later remembered what the implications were.

I don't remember any of the pure scale big machines having the problem but then again my memory starts getting faulty with airplanes in the 500 to 1000 range.

As Dick and others mentioned, the very airplanes that could benefit the most seemed to be the worst offenders.