I fly out of OAK weekly and it's not just the understaffing. On Wednesday the 27th they had multiple ID checkers, one imager and two x-rays going. Nevertheless, they still had Pre-Check shut down and there were numerous blue shirts just sort of milling around. If you were pre-check, they just parked you to the side but this is not unusual. Normally, an agent would come over and escort you to a non-PC x-ray and except for taking your laptop out, it was the standard PC process. This time, after 5 minutes with no escort, everyone who was parked gave up and went through the non-PC process.