That's not how hours work. Being discharged doesn't "delete" the hours you put into volunteering...
If this is true, I would emphasize this (how much you loved the program, not the discharge) if your volunteering comes up in interviews. On the other hand, none of my dedicated volunteering came up in interviews, and I had a lot of it.
Unless something has changed in the last year, schools will not contact any of those people you listed on your activities list. Not that they couldn't, but they just have no reason to.
I can't answer that for you. Where do your draw your moral/ethical line in the stand. Is omission of something relatively inconsequential but could cast a shadow on your application something you consider lying?
What I can say is the chance of them reaching out to your volunteering contact unprompted is about as likely as a snowball surviving a summer in the Sahara.
My question to you would be more about how this was an issue in the first place. From what you say it sounds like it's the program's fault. Did you reach out to them and try to make a reasonable work around? This sounds like pretty harsh treatment of a volunteer.
