[Conan the Librarian]

You are right that you wouldn't see the actual star go in, but, you can see the effects of the gravity on the star BEFORE it goes in. Until the ingoing matter crosses the event horizon, the gravitation effects would be pulling and tugging on the star, stretching it like a strand of spaghetti. Besides that, the gravity would also slow down the light coming from the area, thus shifting the light into the red end of the spectrum.

Then, as the matter from the star does cross the event horizon, the gravity differences from one side of the star, and even one side of individual atoms, rips the star or atom apart, releasing enormous amounts of energy, some of which goes toward the black hole, some of which goes out into the universe.

Black holes aren't like what they show in the movies. If the Sun became a black hole all of a sudden, gravitationally we wouldn't notice, as the gravity wouldn't change. It's not like a giant vacuum cleaner.

[Nathan Zachary]

"Until the ingoing matter crosses the event horizon, the gravitation effects would be pulling and tugging on the star, stretching it like a strand of spaghetti. Besides that, the gravity would also slow down the light coming from the area, thus shifting the light into the red end of the spectrum."

Jupiter(?) stretches out comets like speggetti all the time, that's why it's known as a comet killer. As a comet approaches any large bodys' gravitational field, it accellerates, this would "shift' it's light to the red end of the spectrum as well. There is nothing to say that these observed events aren't simply smaller stars passing near larger bodies we can't see, speeding up as they enter their gravity field and getting pulled apart. In fact if one of these objects passes behind one of these large bodies, it would look as if it was ate up.
And while black hole theory is worked to fit spiral shaped galaxies, it doesn't fit those that aren't. These odd shaped galaxies shouldn't exist, but they do. Excuse me for not using the correct terms, But I think you know what I'm talking about. I don't pay a whole lot of attention to this stuff, just in passing.