I'm not having a go or anything, but I don't know where you people have been living the past six years. There are plenty of cases of people denied exit from the u.s. and who are not under arrest or who are arrested solely due to racist profiling.

The most frequent type of exit prevention involves an ordinary traveler trying to board an international flight at a u.s. airport. The CBP or whatever those clowns are called now will stop the traveler in the boarding pier based on an established religious-racial profile and begin going throgh their hand baggage and shoes until they find cash. Regardless of the amount of cash the traveler has, they then proceed to grill him/her, asking idiotic questions in true post-911 fashion about links to terrorism, etc The interrogation will often result in the person missing their flight and having to argue with the gate agent about reaccomodation on another flight.