My GF is visiting the US on a 6 month visa which expires on March 1st.

She would like to fly out of JFK on a flight which departs at 12:30am on March 2nd, ie: 30 minutes after midnight. As boarding will take place at 11:30pm or so, she will be ON THE PLANE before her visa expires. And she will probably clear outbound immigration by 10:30pm or so.

Is this a problem? How tight are they about these things? Of course the final call is up to the person stamping the passport, but could they possibly be so uptight as to make a problem for her?