From WENN.com

The 22-year-old Harry Potter star was flying solo last month (Dec12) when the embarrassing incident occurred at John F. Kennedy International Airport in New York, and she reveals it is not the first time she has been mistaken for an unaccompanied minor, usually deemed to be children under the age of 14.

In a series of posts on Twitter.com, she writes, ""Passport control: 'Unaccompanied minor?' Me: 'Sorry?' Passport control: 'Where is ur (your) guardian?' Me: 'I'm 22!!!!!!!' Never wearing a back pack again... The really sad thing is that this is not the first time this has happened.""