Why doesn't an outside observer measure the mass of a black hole as being located at the event horizon (instead of the center) due to time dilation. I imagine light passing close to a black hole would bend differently depending on whether the mass is at the center versus at the event horizon, and that could be measured.
Also, since gravity travels at the speed of light, and light inside the event horizon can't escape, and spacetime itself is warped to the point where it rotates around the black hole, then how can gravity (or gravitational waves or energy) escape the black hole if it originates at the center? That wouldn't be an issue if black hole mass were instead located at the event horizon.