First, Stanford will grant free tuition to some capable middle-class students. The ruling elite's noblesse oblige sensibility has been dormant for at least a generation, so this may be an attempted restoration. The policy is less useful as a marketing ploy for low-income social groups whose children lack Stanford's prerequisites. Second, significant life experiences cause epigenetic changes in brain chemistry that subsequent generations inherit. Good experiences like occupational achievement, successful romantic conquests, and wealth-enhancing choices thus increase genetic quality. Bad experiences for less fortunate people (like stress from child abuse or abandonment) decrease inclusive fitness.
The connection between the two items deserves explanation. Upper-class citizens tend to have above average life experiences. They obtain high-quality social goods like education, jobs, and romantic relationships with greater ease and frequency than lower-class people. These kinds of people comprise the vast majority of the student body at Stanford and other top schools that won't need a tuition waiver. They will not willingly associate with anyone from the free-riding minority who do not inherit robust epigenetic markers.
The children from rich families who have to pay for college usually refuse to socialize with anyone getting a free education. I have experienced this phenomenon personally at both the undergraduate and graduate levels. Economically disadvantaged students cannot fully benefit from a Stanford education if elite students shun them from their networks. Children of rich families at elite schools query each other's backgrounds all the time. They also consider visual markers like brand-name clothing and cars. It is easy for them to pick out the lower-class students and label them as undesirable. Their parents raised them to behave that way to preserve their family's way of life.
Elite families have long obsessed over perpetuating their bloodlines. Science now has proof that humans can self-select for genetic quality. Good epigenetic effects among the elite class will keep them well-suited for handling the stresses of high-powered occupations. Success begets success, and successful people will mate with each other to perpetuate ruling class solidarity. Wealthy people can afford trichostatin A treatments to wipe their mental slates clean and raise the epigenetic responses they will pass to their progeny. The poor may not have such an option; I can see the Affordable Care Act's controls ruling trichostatin A an elective treatment not covered by the generous taxpayer. University tuition waivers for the poor will probably not include hormone treatments to wipe away bad genetics.
Stanford and other schools can afford to throw table scraps to the lower classes while the Federal Reserve inflates asset markets. That luxury will evaporate with the next market crash. University endowment growth after the 2008 financial crisis is entirely a function of central bank monetary stimulus. The American variant of Western civilization will still have the Horatio Alger legend and other such useful myths in its future. It will have less interaction between social classes as the epigenetically fit offspring of elite families avoid their less fit fellow students at top universities.