Yes, many times.
In the US it's no problem, there are no exit immigrations.
The only time I've been nervous about catching an international flight was from HKG->SFO when there was a small line for exit customs. I showed up to the airport about 45 minutes before my flight and their lack of TSA-esque security made up for waiting to get my passport checked. I got to the gate just as they started boarding my group.
The only time I've been nervous about catching an international flight was from HKG->SFO when there was a small line for exit customs. I showed up to the airport about 45 minutes before my flight and their lack of TSA-esque security made up for waiting to get my passport checked. I got to the gate just as they started boarding my group.