I knew a women who felt it was her moral duty to fight vaccinations. She had no issue forging documentation saying her kids had gotten vaccinated when they hadn't.
I've heard this is common among the anti-vax crowd. Not saying it is what happened in this case, just giving a personal anecdote.
You can get out of vaccinations in many situations with a) a doctor's express diagnosis that you should not be vaccinated or b) claiming to have a religious reason that prohibits vaccination.
These methods might not work for all universities, but I know they work for some.
I've heard this is common among the anti-vax crowd. Not saying it is what happened in this case, just giving a personal anecdote.