And it works pretty good, if you can get the idiots to turn it in when they leave. But since they don't turn it in and INS won't let the Inspectors do outbound inspections, it don't work worth a damn.
Now that you mention it, every country I've flown out of except the U.S. inspects the passports and claims or cancels the visa documents. The only other exception is Japan, where I have a long-term residence and multiple re-entry permit.
If you are checking in for an outbound flight from the U.S., the only people who will ever inspect your passport are the airline employees, because the airline can get stuck to provide a return flight if they let someone board without a valid visa to the country of destination.
Border controls in the U.S. remain a farce even after 9-11.