I don't have anywhere near the background to fully understand the concept, and maybe this is a question that comes from reading too much sci-fi (or focuses too much on a practical question of a still very theoretical proposal), but isn't one of the main concerns with relativistic spaceflight the intense amount of energy which would be discharged by a collision with atomic or molecular elements of the interstellar medium?

Are there any other proposals out there today which address the risk of travelling through the interstellar medium at a high percentage of c?