^^ In that case, the student AND the guidance counselor both broke the rules. However, as the student was rejected from Stanford, I seriously doubt Stanford publishes a list of rejected SCEA students and distributes it to other colleges. So, it’s unlikely that Stanford or MIT are aware of the situation, so they don’t know it looks suspicious. The kid, and GC, got away with it (this time), but that kind of situation risks not only the GC’s job, but also risks a high school being placed on a college’s blacklist for a number of years – which is why most honorable GC’s don’t do it, as there is more at stake than just one kid’s acceptance.
FWIW: The other option – and it happens quite frequently on College Confidential every year about this time – is that kids lie, brag or tell alternate facts, which is usually what occurs in situations like this one. Without even knowing the people involved, I would place MORE trust in a GC to not let this happen, rather than what a kid says they did. I bet if you checked with this kid’s GC, you would find the story is false.