!!
I will always do my utmost to resolve any 'dangerous' luggage issues - cycles wedged in doorways is one of my favourites - by when the situation gets extreme I will accept defeat and let them put their suitcases etc in whatever spot they are able to wedge them, it simply causes to much delay aggro to go policing every doorway at every stop. I also tend to work on the basic principle that if you have people stood all the way down every aisle and in every doorway, an evacuation is not going to be orderly or pretty, and anything in the way is likely to be kicked out of the door rather quickly!
In an ideal world of course, none of this would happen, and standees in vestibules wouldn't be allowed. But until there is an enormous order for extra rolling stock, you just gotta' make the best of what you've got it seems. I would agree entirely with your thoughts on the Guard's van!