Yes it isn't a wrong thing or a big thing that the IT dept should deny
Now the real question is whether the company she works for has a policy for BB devices ; if its her personal blackberry phone then they might just configure her exchange server account on her phone.
Nokia Mail for exchange, allows dynamic updates to calendar, mail, contacts, push notifications of new email and calendar events.
If the company she works for is already using BES they might have a policy so they can remote wipe the phone data incase of lost or damage or if she leaves work (if its a work phone)
She can always configure her exchange account on mail for exchange for nokia and still have her Blackberry
I would still suggest that blackberry is more superior in terms of usability but thats a personal choice (i dont own a blackberry - but have heard very good things about it from my clients / collegues).