Out of all the theoretical propulsion systems, THIS is pretty much the only one that we know would work without novel (made up) physics like negative energy, etc. In fact, I don't really think we'd need new/novel technology to test this. Biggest hurdle is getting into the right position with respect to a black hole to do this in the first place.
There are much simpler propellant-free ideas for producing relativistic speeds that respect known physics. I particularly like the resonant Photonic Laser Thruster:
> Out of all the theoretical propulsion systems, THIS is pretty much the only one that we know would work without novel (made up) physics like negative energy, etc.
Light sails are totally feasible too, depending on whether you consider them a propulsion system.
