What would be the effects if all the territory of Germany gets covered by a force field, similar to how the one in the game Gothic works. The forcefield allows humans to go inside but if they try to leave they instantly die. Anything thats not human flora, fauna, minerals, etc. can be transported back and forth safely.
This field is applied right after ww1 ends.
Scenario two: It happens right after world war 2 ends.
Scenario three it happens at the height of the cold war.
Scenario four it happens in the modern day.
Question of what is "all the territory of Germany"? For instance on 11-11-18 does that include overseas colonies which are now all pretty much allied occupied but still technically German possessions? Does it include any territories that Germany might have annexed during the war, especially in the east? What would be the situation of German islands - for instance Heligoland? That is some way out into the N Sea and there are I assume others in the Baltic. Are they included and if so is there some sort of extension of the barrier from the German mainland to them. If not then many of those islands could end up totally isolated. If there is such an extension that's going to be a death zone for anyone inadvertently crossing it the wrong way which is going to be an ongoing problem.
Similarly with May 45 technically there is no German government or state, as a result of the unconditional surrender policy. If you mean the borders imposed by the allies after the peace, although they had formally been decided before the surrender their not implemented yet. If the territory over which the prior German government claimed to be 'German' that's going to be a much larger region. Also again with the Cold War option technically there is no German state but two separate nations with different names.
Assuming for 11-11-18 the boundaries are as defined before the war then its going to cause a lot of problems. There will be no practical annexations and a lot of non-Germans, such as Poles in Prussia and Posen provinces, forced labourers, possibly a lot of POWs and of course diplomats and traders now have no capacity to return home or in the case of those who lived inside those boundaries pre-war to escape German rule.
At the same time there are a lot of Germans outside the barrier and depending on the reactions of the allies many may not be allowed to return at least in the short term. They will be suspicious that the barrier is some sort of German trick to avoid the results of their defeat. It will take some time to realise that only one way traffic is allowed and the costs of trying to escape the affected region. There will be a fair number of deaths occurring until this is widely accepted.
Also while non-humans and material are not directly affected moving equipment out of Germany will be disrupted until someone finds a way to do it without humans actually passing the barrier. A solution, once the parameters of the effect are understood would be a train which backs up to the barrier with wagons passing through but the cab itself staying inside the zone. Those wagons are then decoupled and attached to another train outside the zone. Possibly something could be sorted out for canal/river traffic but that could be more awkward.
Of course this also means that Germany has no way of forcing people to send goods inside the zone. With an hostile and distrusting allies controlling most of the border there could be a blockade imposed until Berlin lowers the barrier - which of course they can't but that might not be realised for some time.
There will be issues inside Germany with the country in a fair level of chaos and also any commerce with the wider world affected. You could see both left and right wing fanatics opposing the only recently established civilian government that was handed the poisoned chalice of coming to terms with the allies. That could mean further conflict and destruction inside Germany and also no clear government to try and communicate with the allied and other outside nations and groups.
Similarly while the quick collapse of the German army in the west is secured with most either surrendering or fleeing into the zone and ditto with Germans in the Balkans and the Ottoman empire this also isolates the Germans occupying the rest of Poland, much of Romania and other areas across much of the former Russian empire. Does this give the Soviets a better chance of securing an empire in the east or the removal of any remaining German threat mean that the allies are more willing/able to intervene against the Soviets in the east?
Of course that its only humans that are blocked from passing the barrier - one way anyway doesn't mean that conflict across the barrier is impossible. Although in the short term that would largely be limited to artillery bombardments unless things get really nasty.
Anyway a long enough post here so won't consider the other options for the moment.