The idea I have is that this makes a measurable difference. The idea is combined with the idea that each finite observer acts rationally on it's available information, in order to maximize it's chances of survival and persistience.
This means also that it's RATIONAL to argue like you do. Ie. the possibility is vanishingly small, therefore we ignore it. This is in line with rational action. I just suggest that this should be formalized and taken seriously.
The conclusion is that the laws of physics have to evolve, as seen by any observer. Locally effectively static laws are simply a local equilibrium, due to local negotiation. The best analogy is with emergence of social laws.
Edit: Humans often act AS IF, "rare events" NEVER happens. This is rational, because the information processing agent has limited resources, and it's simply not rational(from a gambling point of view) to occupy resources for such rare events, as you can use the resources more intelligently.
The action of a given observer, could follow from a rational aciton principle, (in an entropic sense) from it's subjective view of the laws of physics. These evolving laws are possible also a key to unification. So I do not think the points I raised are just conceptual only. I think there are constructive points that could be used to find a better framework.