While guarantees that would remove all such issues ("leave me on system 'x' with no shifting sands forever!") are costly and therefore undesirable within a cloud context, this describes but one example of an edge case that could be elegantly handled by informing the node that it must go down and come up again a while later, after which its swapped-out guts with the potential to cause issue might be more easily resolved.
I would generalize this in to a broader statement: "Environment-related guarantees do need to be further specified on commercial cloud providers, and a better interface given to clients when changes are scheduled".
Other areas of cloud APIs (particularly cross-cloud) that are presently missing: legal jurisdiction, site/availability zone enumeration, available hardware configuration enumeration (including network bandwidth policies), resource guarantees (including network bandwidth).
I recently posted these as bugs to CIMI @ deltacloud's teambox - https://teambox.com/#!/projects/deltacloud/task_lists