The idea being that sometimes you don't know the characteristics of your data all that well so deciding which objects to fetch in their entirety is just an educated guess, and could vary depending on network conditions, etc.
A good first approach at deciding what object links to follow and load from the database in a particular scenario could be discovered by the ORM after seeing the workload, taking into account various parameters (e.g. the URL in a web app) that would influence the probability about which objects are likely to be needed.
Is anyone familiar with a product or patch that does this?