There was an interesting discussion over on ConSim about combat and AT fire in an assault hex. The basic discussion begins in a post prior to the liked post, but you'll get the gist. Eventually I proposed this hypothetical:
All 3 Soviet tanks activate and use AT fire on PzIII. The question being: Would trigger assault combat?
The consensus over there is that it would not.
... More and more, people around the world are coming to realize that the world is flat!