This flaw in teleportation logic hinges on the assumption that there is an absolute reference frame- which as far as I'm aware there isn't. There is real science behind teleportation, and from what I've seen the frame of reference of the origin is what determines the endpoint. If you COULD manipulate the frame of reference as well, you could teleport a small rock an inch forward, but with the frame of reference of a near lightspeed object to create a crazy projectile.

Basically, you'd still need to follow the rules of conservation of momentum and energy, or it could be broken.