Just to provide a specific counter-example, MIT and Caltech each admitted one student from son’s very small (<50 graduates a year) and very well-known special program last year.
Both of them ended up attending elsewhere, and Caltech’s admission rep did lament the fact that they routinely lose students to MIT in a small group meeting with prospective students son was invited to.
This year, MIT and Caltech admitted two students each from son’s class in EA.
There may exist schools that retaliate in the way @CAEngineer describes, but, leaving moral judgement of their institutional behavior aside, Caltech is certainly not one of them (and neither is MIT). Unlike some other schools that are trying to play the rankings game, they admit the best and let the yield chips fall where they may.