I found this very interesting and will give it a go when I get my iPhone 4 here in Oz...
"Theres something thinner than tape, and much more attractive
I used to be an R&D;engineer in fuel cells, where corrosion and passivation issues are very important.
Stainless steel doesnt corrode because it develops a thin layer of transparent, non-flakey oxides (passivation) on the nickel and chrome in stainless. oxides dont conduct electricitybelieve me, they dont. But such oxides dont interfere with the radio signals (photons) being emitted by the metal an
Its possible that Apple knew of this problem and dismissed it. I note that in almost all the videos by users, they hold the video camera with their right and hold it with their left. So normal, right-handed use might make it so this is a rare phenomenon on average.
I dont yet have my version-4 phone (still have my 3GS) But if it were me, the first thing I would try (be careful if you try this) is to make sure the stain band is very clean and free of oils.
To clean, try one part Windex in three parts distilled water and dampen (not soaked) a rag. Wipe down the edge to make it completely free of oils
Then to passivate the stainless (make a very, very thin piece of tape), I would rub it down with a damp rag with distilled or tap water (if it isnt really water). Let the dampness dry. Repeat several times. You can even use a hand-held hair drier on low (~140 °F) to accelerate the drying and promote deeper passivation.
A mild acid, like vinegar will really passivate stainless quite well. But you REALLY have to be careful; ensure the rag is only *damp*. You should also on a small spot on the bottom of the phone to make sure it doesnt discolor the band.
I should think that skin would have a terrible time galvanically connecting to the stainless and bridging the different antennas if the stainless is fully passivated."
Hope it helps...