As long as she is primary on the account, and has her account info/photo ID, I don't think she'll have any problems.
When I worked at Apple, the store was in a touristy area, and we did upgrades for out of town folks all of the time. The only problem was when selling an iPhone with a new line of service to someone from outside of the area, as it would always pick a telephone number with an area code local to the store. Not sure if they fixed that yet.