we have something here as exciting as cold fusion or polywater. it seems to violate newtons second law so people are looking for the escape clause. If it's real it's a huge deal because it means the fundamental problem of space travel--- bringing your propellant--- is permanently solved modulo the nitty gritty of making it more efficient.
On the otherhand, like polywater and cold fusion it's likely a reproducible experimental error that's not been identified yet. 3 groups have independently observed it so far.
My guess: it's just ions sputtered off the walls and accelerated or it's attraction towards an induced dipole in the room, neither of which would be exciting.