I agree. I would like just to add that a door has several functions, and one of them is being a border line, not only physical one but also moral, legal, psychological, etc.
For example, if there is a picket fence around a property it does not mean that this fence must be impenetrable, i.e. to have barbed wire, movement sensors, etc. But still it is a good picket fence which have got many useful functions.
And people should not think, - oh, this picket fence is not secure, so I can cross it and do whatever I want on this property.