The interesting quasi-legal question: Is it a valid defense to claim that others do the same?
Mrs. Marcos seems to rely on a kind of a Tu Quoque defense (“Hey, you also did it!”), which is often rejected as irrelevant, being ad hominem. But I believe Tu Quoque works in certain situations where the prosecution violates equal protection and/or due process.
At least at some gut level, Tu Quoque ought to be a valid defense if just about everyone else did the same. Otherwise, we would live in a society of hypocrites.
See the GMA interview with Mrs. Marcos.