The only reason for these operators to do memory sharing would be if it allowed them to oversubscribe RAM--is there any reason to believe any of them are doing

The only reason for these operators to do memory sharing would be if it allowed them to oversubscribe RAM--is there any reason to believe any of them are doing that? It seems like it would lead to extremely noticeable and severe performance or stability issues in edge cases unless the provider required you to run a specific image on your instance.