I wouldn't worry so much about the event horizon so much as what is right outside of it.
The tidal forces and the x-rays resulting from said forces are pretty much lethally intense.
The tidal forces and the x-rays resulting from said forces are pretty much lethally intense.
Tidal gravity is equivalent to spacetime curvature, so it's there whether or not there is matter falling into the hole; the term "tidal force" is sometimes used to refer just to that fact. But X-rays won't be produced unless enough matter is falling in and being acted on by the tidal force. If there were no large quantities of matter falling in, a very small object like, say, an astronaut in a rocket ship, could fall in and not encounter any X-rays, but the tidal force would still be there (and could potentially pull his ship and him apart). I wasn't sure if that distinction was clear.
In the ordinary universe this often plays out on small moons in a low orbit around very large planets such as Jupiter.
A definition (http://en.wikipedia.org/wiki/Tidal_force): "The term tidal force is used to describe the forces due to tidal acceleration." You can't have acceleration without an object being accelerated.
Not trying to split hairs here, but to try and establish if it's possible to have a force that's not acting on anything.
This is one way of looking at it, but it's not very general. The more general way of looking at it is to look at two nearby "test objects" (meaning objects so small that they don't affect the gravitational field enough to make a difference), both in free fall, that start out at rest relative to each other. If they don't stay at rest relative to each other, then tidal gravity is present.
The term "tidal force", on the more general view, refers to forces felt by objects that are not allowed to follow the free-fall paths that tidal gravity is trying to make them follow. For example, consider a small piece of the Earth on the side facing the Moon, and another small piece on the side opposite the Moon. If these two pieces of matter were in independent free-fall orbits, they would separate due to the tidal gravity produced by the Moon. Since the two pieces of matter are not independent--they are both attached to the Earth--they both feel a "tidal force" because they are being prevented by the rest of the Earth from following the "normal" free-fall orbit they would follow due to the Moon's gravity if they were not attached to the Earth.
if it's possible to have a force that's not acting on anything.
If you don't like using the term "force" when there's no object feeling the force, then you can just use the term "tidal gravity", as I did above, to refer to the underlying spacetime curvature that, when objects are present to feel the force, causes "tidal force". So tidal gravity can be present even when there is no object feeling tidal force due to the tidal gravity.