A reactionless thruster that (apparently) really works - no, seriously!

On 9/10/06, Ian Woollard wrote:
(...)
> But for the reactionless thruster to work in the same way, I believe
> it would need a prefered reference frame since it has nowhere to store
> the energy (no propellant) that it has gained from accelerating. That
> violates the relativity principle, and hence also violates Maxwell's
> equations.
(...)

Lets suppose that the effect being measured in that machine is real
and confirmed by several independent sources, and apparently it is
violating conservation of momentum, action and reaction, etc. Could it
be that in fact the machine *is* transferring momentum to something,
but through indirect and difficult to detect means?

For instance, suppose a thought-experiment involving an engine able to
be repelled instead of attracted by gravity. This thing would move
upwards in a seemingly "reactionless" way. In reality, though, it
would balance momentum with Earth in the same way that a falling
object does (though with opposite signs). As for energy, one could
postulate that the energy needed for this engine to produce this
negative weight would equals the potential energy of this negative
weight relatively to infinity.

What I am trying to say is that if this "reactionless" thing works
then the conservation laws are probably not being thrown away; they
are just being obeyed in subtler ways. Think of how the neutrino was
discovered based on an apparent violation of energy conservation.