I don't think Arc Map remembers the exceptions. It has been a while, but my recollection is if you validate again, the previous exceptions are lost and you have to redo the exceptions. A little frustrating.
ArcMap does remember the exceptions and stores them. I'm able to see the 3000+ exceptions I've previously marked in the past 3 years.
Nice to know that it does remember. I'll have to confirm that for myself next time I have to use it. I just recall wanting that functionality for the topology tools and not seeming to be able to get it; that is, it seemed like whenever I re-validated that it would re-highlight those that I had marked as exceptions.
I imagine it would be tough to store the exception and then keep track of which features are related to the them so that the error exception would be removed if any of the related features were modified.