[ggoss]

There is a net zero electric field inside, true, but isn't that because a charge accumulates on the inside surface of the cage that is equal and opposite to that induced on the outside surface?

With regard to #1, I agree, but the degree of RF leakage is not universally small - it depends on the frequencies you encounter and the properties of your cage (material, mesh thickness and "pore" size, etc). As frequency increases (and wavelength decreases), your pore size must decrease to effectively block it, eventually becoming a solid shell (through which propellers will, of course, generate no thrust). I agree with #2.

[Florin_Andrei]

> There is a net zero electric field inside, true, but isn't that because a charge accumulates on the inside surface of the cage that is equal and opposite to that induced on the outside surface?

No. In a conductor, all free charges migrate to the outside surface.